A Tutorial on BAPI

A tutorial on

Business Application Programming Interface (BAPI) Compiled by Sudhanshu Singh

A Tutorial on Business Application Programming Interface_____________________________

Content Business Application Programming Interface (BAPI)

3

Business Object Repository (BOR)

4

Transaction Model for Developing BAPIs

5

Defining and Implementing the BAPI

8

Frequently Used BAPIs

9

Defining a BAPI Scenario

11

Defining a BAPI and Its Interface

13

Determining the SAP Business Object and Its Key Fields

14

Defining the Interface Structure of the BAPI

15

Naming Parameters in the Function Module

16

Specifying the Required Objects in ABAP Dictionary

17

Naming the Method in the BOR

18

Naming Parameters in the BOR

18

Creating Individual Programming Objects

20

Conversion Between Internal and External Data Formats

21

Converting Between Internal and External Data Formats

22

Application Example

23

Defining Methods in the BOR Using the BOR/BAPI Wizard

25

Example of a Function Module

27

Testing the BAPI

28

Releasing and Freezing the BAPI

29

Programming BAPIs

30

Programming Change BAPIs

31

Programming Replicate/Clone BAPIs

34

Programming Value Ranges

36

Internal and External Data Formats

37

Reporting Errors

39

Providing Input Help (F4 Help)

42

Improving the Performance of your BAPI

44

Enhancements to Existing BAPIs

45

Customer Modifications of BAPIs

48

Implementing BAPIs in ALE Scenarios

50

BAPI Implementation Checklist

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Business Application Programming Interface Definition A Business Application Programming Interface (BAPI) is a precisely defined interface providing access to processes and data in business application systems such as R/3. BAPIs are defined as API methods of SAP Objects. These objects and their BAPIs are described and stored in the Business Object Repository (BOR).

Use BAPIs can be called within the R/3 System from external application systems and other programs. A BAPI call can either be made as an object oriented method call or as a remote function call (RFC). BAPIs are a global communication standard for business applications. Examples of what BAPIs can be used for include: ƒ

R/3 satellite systems

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Distributed R/3 scenarios using Application Link Enabling (ALE)

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Connecting R/3 Systems to the Internet using Internet application components (IACs)

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Visual Basic programs as front ends to R/3 Systems

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Work flow applications that extend beyond system boundaries

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Customers' and partners' own developments

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Connections to non-SAP software

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Connections to legacy systems

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Business Object Repository (BOR) Definition The Business Object Repository (BOR) is the object oriented repository in the R/3 System. It contains, among other objects, SAP Business Objects and their methods. In the BOR a Business Application Programming Interface (BAPI) is defined as an API method of an SAP Business Object. Thus defined, the BAPIs become standard with full stability guarantees as regards their content and interface.

Use With regard to SAP Business Objects and their BAPIs, the BOR has the following functions: •

provides an object oriented view of R/3 System data and processes. R/3 application functions are accessed using methods (BAPIs) of SAP Business Objects. Implementation information is encapsulated; only the interface functionality of the method is visible to the user.

•

arranges the various interfaces in accordance with the component hierarchy, enabling functions to be searched and retrieved quickly and simply.

•

Manages BAPIs in release updates. BAPI interface enhancements made by adding parameters are recorded in the BOR. Previous interface versions can thus be reconstructed at any time. When a BAPI is created the release version of the new BAPI is recorded in the BOR. The same applies when any interface parameter is created. The version control of the function module that a BAPI is based on is managed in the Function Builder.

•

Ensures interface stability. Any interface changes that are carried out in the BOR, are automatically checked for syntax compatibility against the associated development objects in the ABAP Dictionary.

Integration You should only define a BAPI as a SAP Business Object method in the BOR if the function module that the BAPI is based on has been fully implemented. Full access to the BOR is restricted to the persons responsible for the objects involved and for quality control. BOR-BAPI Wizard The BOR-BAPI Wizard assists with creating new BAPI methods in the BOR. It takes you through the creation process step by step.

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Transaction Model for Developing BAPIs Purpose The transaction model in which BAPIs are used determines how you have to program BAPIs. The transaction model described here has been used to develop BAPIs for R/3 Releases 3.1 and 4.0A. Logical Unit of Work (LUW) and Statelessness Within the context of this transaction model a transaction represents one processing step or one logical unit of work (LUW). When a transaction is called, database operations are either fully executed or not at all. The whole transaction must be programmed to be stateless. This transaction model requires that: •

no data is imported that may indirectly affect the result. If a transaction is called more than once, each call must have the same result. For BAPIs this means, for example, that Set or Get parameters cannot be used. However, you can keep Customizing data in a global memory as this data remains unchanged even if transaction calls are repeated.

•

there must be no functional dependencies between two transactions.

•

either all relevant data has to be changed in the database or none at all.

The following sections describe how the transaction model effects BAPI development: •

Using the Transaction Model in Release 3.1

•

Using the Transaction Model in Release 4.0A

Using the Transaction Model in Release 3.1 Purpose The example below of an external program calling a BAPI to change data in an R/3 System, illustrates how the transaction model affects BAPI development in Release 3.1. Assume the transaction was written in, for instance, Visual Basic and that data is to be changed in the R/3 System only. The RFC connection is live the whole time the external program is logged on to the R/3 System to avoid having to connect and disconnect repeatedly. When the RFC connection is already established, an RFC call does not essentially take up any more CPU time than a direct call to the function module from within the R/3 System. There is one BAPI call for each transaction in the transaction model supported in 3.1. BAPIs can only be called synchronously. A BAPI call is essentially the call of the underlying RFC capable function module.

Process Flow The process flow of the program consists of the steps below (see graphic): Log on _________ __________________________________________________________________ 5

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..... (Visual Basic source code) Call BAPI to read and/or change data ..... (Visual Basic source code) Call BAPI to read and/or change data ..... (Visual Basic source code) Log off

Prerequisites What do the terms "LUW" and "statelessness" mean to BAPIs that are implemented in the framework of this transaction model? If a transaction represents one Logical Unit of Work and in addition is supposed to be stateless, BAPIs are affected as follows: •

Initial state each time a BAPI is called A repeated call of one BAPI must produce the same result. Only data that is not affected by the execution of the BAPI, for example, customizing data, can be buffered.

•

No functional dependency between two BAPIs A BAPI call must not be negatively affected by an earlier call of another BAPI. A follow up call must not presuppose an earlier call.

•

All or nothing principle A database change, for example, creating a new sales order, must be carried out completely or not at all (LUW).

This is why BAPIs to be implemented in 3.1 are created with integrated commit control. The "Commit Work" command is always invoked at the end of the function module of a BAPI that modifies data.

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Using the Transaction Model in Release 4.0A Purpose In Release 4.0A the Commit control must be taken out of write BAPIs, that is, those BAPIs that cause database changes. However, the existing transaction model used in Release 3.1 should not be changed. This is achieved by using the RFC capable function module BAPI_TRANSACTION_COMMIT which executes the command "Commit Work". This procedure is required because BAPIs are used for continued development of the R/3 System, for example, for separating individual R/3 components. If this is the case, BAPIs must support the transaction model used in the R/3 System.

Features A program based on this transaction model could consist of the following steps (see graphic): Log on ..... (Visual Basic source code) Call BAPI to read and/or change data Call BAPI_TRANSACTION_COMMIT ..... (Visual Basic source code) Call BAPI to read and/or change data Call BAPI_TRANSACTION_COMMIT ..... (Visual Basic source code) Log off

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Defining and Implementing the BAPI Purpose A BAPI is an API method of a business object and is defined as such in the Business Object Repository (BOR). However, a BAPI is implemented as an RFC capable function module which is maintained in the Function Builder. For function modules that implement BAPIs certain standards and rules must be adhered to over and above the standard programming rules for function modules. This section describes how to define a BAPI and which particular guidelines to comply with. When implementing BAPIs follow the requirements below to ensure you achieve consistent behavior and representation of BAPIs as object oriented methods of SAP Business Objects. There is a range of BAPIs that provide basic functions and these can be implemented for most of the SAP Business Objects. For information on these BAPIs see the section Frequently Used BAPIs. Check if the BAPI you want to implement is in one of these general categories.

Process Flow The process of defining and implementing a BAPI consists of the following steps: •

Describing the Scenario in which the BAPI is used

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Reviewing the BAPI Concept and BAPI Scenario

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Defining a BAPI and Its Interface

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Creating Individual Programming Objects

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Testing the BAPI

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Releasing and Freezing the BAPI

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Frequently Used BAPIs Definition Some BAPIs and methods provide basic functions and can be used for most SAP Business Objects. These BAPIs are: BAPIs for Reading Data The following BAPIs provide you with read-only access to data in the associated Business Object: •

GetList With this BAPI you can select a range of object key values, for example, company codes and material numbers. To specify appropriate selection requirements the calling program must pass the relevant parameters to the interface. The key values selected by the BAPI GetList are returned to the calling program in a table, together with other useful information, for example, short texts. The key values can then be passed on to another BAPI for further processing, for example, the BAPI GetDetail, as listed below. For further information on programming GetList BAPIs see Programming Value Ranges.

•

GetDetail The BAPI GetDetail uses a key to retrieve details about a specific instance of an object and returns this data to the calling program.

•

GetStatus The BAPI GetStatus is used to query the status of an SAP Business Object, for example, to determine the processing status of a sales order. This BAPI is used only for displaying the status of an object and does not retrieve full details like the BAPI GetDetail.

•

ExistenceCheck The BAPI ExistenceCheck checks whether an entry exists for an SAP Business Object, for example, whether the customer master has been created. You should implement this method as a workflow method and not as a BAPI (RFC capable function module). The method CompanyCode.ExistenceCheck of the business object CompanyCode (BUS0002) is an example of this. This workflow method is indirectly invoked when the calling program instantiates an object, for example, by using GetSAPObject("CompanyCode") from within Visual Basic.

BAPIs for Creating or Changing Data The following BAPIs can create, change or delete instances of a business object: •

Create or CreateFromData The BAPI Create or CreateFromData creates an instance of an object, for example, a sales order.

•

Change The BAPI Change changes an existing instance of a SAP Business Object, for example, a sales order. For more information about the BAPI Change see Programming Replicate/Clone BAPIs.

•

Delete The BAPI Delete deletes an instance of a SAP Business Object, for example, a sales order.

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BAPIs for Replicating Business Object Instances The BAPIs below can be implemented as methods of business objects that can be replicated. For further information about these BAPIs see Programming Replicate/Clone BAPIs: •

Replicate The BAPI Replicate is used by a client system to request clones of business objects in a server system. This method must be implemented for each business object to be cloned.

At least one of the following BAPIs must be implemented for each business object to be cloned: •

Clone The BAPI Clone is used by a system to replicate one business object on another system or to modify one business object that has already been cloned.

•

CloneMultiple The BAPI CloneMultiple is used by a system to replicate several business objects on another system or to modify several business objects that have already been cloned. Unlike the BAPI Clone, the BAPI CloneMultiple can replicate or modify several business object instances at the same time.

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Defining a BAPI Scenario Purpose Before you program a BAPI you should clearly define the processes and situations the BAPI will be used for.

Process Flow To define the scenario the BAPI is to be used for, consider the following issues: •

Which scenario is to be implemented? Every BAPI should be based on a model of a scenario in which it can be usefully employed. You can describe the scenario in the form of a process model.

•

Which SAP Business Objects are involved? From the scenario definition and with the help of the process model you can get information about the SAP Business Objects relevant to the BAPI scenario. Example

In the scenario to be implemented, a BAPI is required to read data about a creditor. First of all, a list of creditors is to be displayed from which a specific creditor can be selected. Then, using another BAPI, specific details about this creditor are to be displayed. The relevant SAP Business Object for this scenario is Creditor. •

What functionality should the BAPI provide and how does it affect related BAPIs, especially the other BAPIs of the SAP Business Object in question? In line with the scenario concept BAPIs must complement each other to create a complete scenario. Their relationships with each other must be clearly defined. Example

To read a creditor's details as described in the above scenario, two BAPIs are required: -

Display list of creditors

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Display details of a specific creditor

The interdependency between these two BAPIs is evident because first the creditor list is displayed to obtain the ID of the specific creditor sought. From this ID, details of this creditor can then be displayed. However, the two BAPIs remain functionally independent of each other, because if the creditor ID is known, the BAPI "Display details of a specific creditor" can be used without first calling the BAPI "Display list of creditors". •

To what extent can the BAPI's functionality be implemented within the scope of the business object? A BAPI should be developed so that it provides functionality exclusively within the context of its associated SAP Business Object. If the data of a different SAP Business Object is to be read or updated then the appropriate interface for this object must be used. The functions or methods of these other objects are used implicitly (delegation principle). Example

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The BAPIs required to read creditor details in the above scenario are only able to access data in the SAP Business Object Creditor. Other object types are not involved. •

Is the BAPI assigned to the SAP Business Object in a meaningful and semantically correct way?

Result Once you have considered these issues you will be able to clearly conceptualize the functionality of the planned BAPI(s). You will also have identified the SAP Business Objects relevant to the BAPI scenario.

Review Purpose In the previous step you created a concept for a scenario a BAPI could be applied to. You also defined relevant SAP Business Objects. Before you implement the scenario and begin defining and developing the BAPI, you should carry out a review of the scenario concept.

Process Flow You should carry out the review of the BAPI scenario in cooperation with all persons involved in the BAPI development and those responsible for quality control in your development group.

Result Start developing the BAPI only after you have successfully completed the review.

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Defining a BAPI and Its Interface Purpose After you have carried out the review of the BAPI concept and it has been accepted, you can start defining the BAPI itself. In this step, you will decide on the names, parameters, and characteristics of the BAPI and determine the structures the BAPI will be based on. Only after you have planned and defined these required details can you start to implement the BAPI, as described in Creating Individual Programming Objects and Programming BAPIs.

Process Flow To define the scope and required components of the BAPI to be implemented, the following steps must be completed: •

Determining the SAP Business Object and Its Key Fields

•

Defining the Interface Structure of the BAPI

•

Identifying the name of the function group, or if a function group does not exist already, planning a name for one. All BAPIs belonging to one SAP Business Object should be stored as function modules in one function group. Ascertain whether a function group has already been created for the BAPIs of the SAP Business Object in question. If a function group does not already exist, then plan a name for the one to be created. You can use the default technical name (object type) of the SAP Business Object as the basis of the function group name. The technical name of a SAP Business Object usually takes the form of BUSnnnn, where n is a number. Use the suffix "nnnn" as the name of the function group. For example, if the technical name of the object is BUS1008 then the associated BAPI function group is called 1008. To ascertain the technical name of the Business Object, open the Business Object in the Business Object Repository (BOR), as described in Determining the SAP Business Object and Its Key Fields. To display further details, for example, the object type, double click the name of the Business Object.

•

Assigning a name to the function module Choose a name that gives an indication of what the BAPI is used for. The naming convention is: BAPI__. For information about naming a method refer to Naming the Method in the BOR. For example, in the case of a BAPI which reads details for the object type Creditor, the name of the associated function module is BAPI_CREDITOR_GETDETAIL.

•

Naming Parameters in the Function Module

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Defining the format for passing the values in the function module interface. Parameters must not be converted before they are passed to and from the BAPI interface. This is because BAPIs are programming interfaces and not end user interfaces. Exceptions are currency codes, ISO codes and fields with an internal key.

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Specifying the Required Objects in ABAP Dictionary

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Naming the Method in the BOR

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Naming Parameters in the BOR

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Determining the SAP Business Object and Its Key Fields

You have to identify the relevant SAP Business Object in the Business Object Repository (BOR) and determine whether the key fields of the Business Object are relevant for your BAPI. A key is defined in the BOR for most SAP Business Objects. This key can consist of several key fields. The contents of these key fields uniquely identify one individual instance of an SAP Business Object. You can differentiate between instance-dependent and instance-independent BAPI methods. Unlike instance-independent methods, instance-dependent methods relate to one instance (one specific occurrence) of an SAP Business Object type, for example to one specific sales order. In the case of instance-dependent BAPIs, the key fields of the corresponding SAP Business Object must be used as parameters in the function module the BAPI is based on so that the associated object instance can be identified. The names of the key fields in the SAP Business Object and the corresponding parameters in the BAPI function module must be the same, because the name links the key fields to the parameters. All the key fields defined in the BOR for the SAP Business Object in question must be used as the parameters in the function module. For further information see Defining the Interface Structure of the BAPI. Example

SAP Business Object Creditor has a key field named CreditorId. This key field must be defined as a parameter with the name CREDITORID in the function modules of the instant-dependent BAPIs for this Business Object. To display the Business Object and its key fields follow the steps below: 1.

Select Tools → ABAP Workbench → Overview → Business Object Browser . The business objects are displayed in the order of the R/3 application hierarchy.

2.

Select the required SAP Business Object in the application hierarchy and double click it to open it.

3.

To display the Business Object's key fields, expand the node Key fields.

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Defining the Interface Structure of the BAPI Purpose In this step you are going to define the BAPI interface, that is, the individual import, export and table parameters required for calling the BAPI. Caution

You cannot use Changing and Exception parameters in a function module which implements a BAPI.

Process Flow To define the interface parameters, proceed as follows: 1. Check whether the key fields of the SAP Business Object are required in the interface. The key fields of the SAP Business Object are some of the most important BAPI parameters. -

If a key value is to be passed to the BAPI by the calling program, the key field must be set as an import parameter in the function module of the BAPI. That way a specific instance of the Business Object is identified. For example, this could be a customer number (CustomerNo) in the BAPIs Customer.GetDetail and Customer.CheckPassword, or the number of a sales document in the BAPI SalesOrder.GetStatus.

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For BAPIs that generate instances, for example, the BAPIs Create or CreateFromData, the key field of the Business Object should be set as an export parameter in the BAPI function module. These BAPIs return one key value, for example, an order number in the BAPI SalesOrder.CreateFromData.

-

For BAPIs that are class methods a key field is neither set as an import nor as an export parameter in the BAPI function module. Class methods are instance-independent and are called without the use of key values. Usually they return a table with a selection of key values. Exceptions are write BAPIs, as described in the list item above.

2.

Specify what other data is relevant as import, export or table parameters for the BAPI. Every BAPI must have an Export parameter return that reports messages back to the calling program. Example

The BAPI to be developed is to read data from the SAP Business Object Creditor. To read creditor details, the calling program has to pass the ID of the creditor and the company code. The creditor data returned is to include general details, specific details and bank details. To map these requirements onto the BAPI interface, the following parameters must be set in the function module which the BAPI is based on: ƒ The key field CreditorID of the SAP Business Object as an import parameter ƒ An import parameter for the company code ƒ A Return parameter that reports messages back to the calling program ƒ A parameter for general details of the creditor ƒ A parameter for specific details of the creditor ƒ A parameter for bank details of the creditor

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Naming Parameters in the Function Module Purpose In the previous step you identified the contents of the interface parameters. Now you can specify the names of these parameters in the function module.

Prerequisites You can only define export, import and table parameters in the function module interface of the BAPI. Give meaningful names to the parameters in the function module interface to give the BAPI an easy-to-use interface. This is because the names you choose for the function module parameters are used in the Business Object Repository (BOR) as the names of the corresponding method parameters. When assigning parameter names follow the guidelines below: •

The names must be in English

•

The names of parameters in the function module can generally be a maximum of 30 alphanumeric characters. The names of parameters in a function module that implements a BAPI can only have a maxiumum of 20 alphanumeric characters, because the names of parameters in the function module must be identical to the parameter names in the BOR, and the latter are restricted to a maxiumum of 20 characters.

•

The names of parameters in the function module must be written in capitals.

•

Choose meaningful names and do not use abbreviations. Example

In the above example based on the creditor scenario, the following parameters were identified: •

An import parameter for the key field CreditorId of the SAP Business Object

•

An import parameter for the company code

•

A Return parameter

•

A parameter for general details of creditor

•

A parameter for specific details of creditor

•

A parameter for bank details of creditor

You could use the following names for these parameters in the function module: Parameters and their Names in the Function Module Contents

Name in Function Module

Parameter Type

Creditor number

CREDITORID

IMPORTING

Company code

COMPANYCODE

IMPORTING

General creditor details

CREDITORGENERALDATA

EXPORTING

Specific creditor details

CREDITORCOMPANYDATA

EXPORTING

Return parameter

RETURN

EXPORTING

Bank details

CREDITORBANKDATA

TABLES

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Specifying the Required Objects in ABAP Dictionary Purpose After you have specified the contents and names of the required interface parameters you can identify and define the required data objects in the ABAP Dictionary. Note the following: •

You can use individual fields, structures and tables as parameters. Every parameter must refer to a Dictionary object.

•

You have to create your own data structures for the BAPI interface that are independent of the data structures generally used in the R/3 application. This enables changes to be made in R/3 applications without affecting BAPIs. Give meaningful names to the data structures you create. Names should begin with the prefix BAPI.

•

Chose meaningful names in English for the structure fields. Up until Release 4.0 ten characters were available for naming structures; from Release 4.0 you can use up to 30 characters. You can use alphanumeric characters and underscores. You can use existing data elements and domains for the fields in the BAPI structures. As of Release 4.0 it is possible to assign English names to the data elements in the ABAP Dictionary. Whenever possible use these names for the field and parameter names. Example

In the example in the previous steps the reference fields/tables shown below were identified for the parameters. The first example here uses structures created in Release 3.1. In this Release structure names had a maximum of 10 characters. The second example shows how you could name the structures more meaningfully in Release 4.0. Parameters and their Reference Fields in Release 3.1 Parameter in the Function Module

Reference Field/Table

CREDITORID COMPANYCODE CREDITORGENERALDATA CREDITORCOMPANYDATA RETURN CREDITORBANKDATA

BAPI1008-VENDOR_NO BAPI1008-COMP_CODE BAPI1008_4 BAPI1008_5 BAPIRETURN2 BAPI1008_6

Parameters and their Reference Fields in Release 4.0 Parameter in the Function Module

Reference Field/Table

CREDITORID COMPANYCODE CREDITORGENERALDATA CREDITORCOMPANYDATA RETURN CREDITORBANKDATA

BAPI1008-VENDOR_NO BAPI1008-COMP_CODE BAPI1008_CREDITORGENERALDATA BAPI1008_CREDITORCOMPANYDATA BAPIRETURN2 BAPI1008_CREDITORBANKDATA

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Naming the Method in the BOR Purpose You can now plan the name of the BAPI method in the Business Object Repository (BOR).

Prerequisites The individual components of BAPI names are identified by the use of upper and lower case letters, for example, ChangePassword. BAPI names must be meaningful and be in English, and can only have a maximum of 30 characters. For example: •

ExistenceCheck

•

ChangePassword

•

GetDetail

If you are implementing one of the frequently used BAPIs use the appropriate generic name. To get an idea about naming BAPIs take a look at existing BAPIs of an SAP Business Object in the BOR. Select an SAP Business Object in the application hierarchy in the Business Object Browser and expand the node Methods. BAPIs are identified by the API indicator (green circle) to the right of the method name.

Naming Parameters in the BOR Purpose The parameter names of the methods in the Business Object Repository (BOR) are based on the parameter names in the function module. You have already named the parameters of the function module in Naming Parameters in the Function Module. Caution

From Release 4.0 the names of the BAPI parameters in the BOR and the names of the parameters in the corresponding function module must be identical. This was not necessarily the case in earlier releases.

When naming parameters of a BAPI in the BOR take account of the following: •

The parameters must be in English.

•

Unlike parameter names in the function module that must be written completely in upper case, the components of parameter names in the BOR are separated by upper and lower case letters. Every new word in the parameter name begins with a capital letter, for example, ChangePassword.

•

A parameter name in the BOR cannot have more than 20 characters.

To get an idea about naming BAPI parameters, take a look at the parameters of existing BAPIs in the BOR. Select an object type in the application hierarchy in the Business Object Browser. Expand the node for the object's methods, then select a BAPI, then finally select Parameter.

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Example

In the example in the previous steps six parameters for a BAPI were identified and names given to these parameters in the function module. The table below shows what the parameter names could look like in the function module and in the BOR. Parameters and their Names in the Function Module and in the BOR Contents

Name in Function Module

Name in the BOR

Creditor number

CREDITORID

Defined as a key field of the Business Object Creditor and NOT as a BAPI parameter.

Company code

COMPANYCODE

CompanyCode

General creditor details

CREDITORGENERALDATA

CreditorGeneralData

Specific creditor details

CREDITORCOMPANYDATA

CreditorCompanyData

Return parameter

RETURN

Return

Bank details

CREDITORBANKDATA

CreditorBankData

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Creating Individual Programming Objects Purpose After you have identified the individual programming objects and given them names you should create them in the R/3 System as required.

Process Flow To create the required programming objects in R/3 the following steps are required: •

Creating the Dictionary objects, for example, structures, fields and domains, in the ABAP Dictionary.

•

Creating the function group in the Function Builder (if required).

•

Creating the function module in the Function Builder.

•

Writing documentation for the BAPI. BAPI documentation is essential because it is very difficult to use a BAPI that has not been well documented. The BAPI documentation must be written in the Function Builder for the function module that the BAPI is based on. Make sure that the documentation is translated into the required languages.

•

Using the program to map the internal data format onto the external data format, as described in Conversion Between Internal and External Data Formats.

•

Writing the program for the function module. Refer to Example of a Function Module. Also, see Programming BAPIs for more information.

•

Defining the function module as a method of the corresponding SAP Business Object in the BOR, as described in Defining Methods in the BOR Using the BOR/BAPI Wizard.

You should then verify that the parameters and parameter types of the method in the BOR match the parameters of the underlying function module in the Function Builder.

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Conversion between Internal and External Data Formats Use According to the guidelines BAPI interfaces should only have English field names. However, in the internal working structures of a BAPI German field names are often used. Moreover in one of the previous steps you created your own structures for your BAPI which are different from the structures used in R/3 applications. This is necessary to be able to freeze the BAPI structure and to maintain a stable BAPI interface, yet at the same time, to enable further development in the R/3 application. For more information refer to Internal and External Data Formats. As a result of these discrepancies the fields of the internal working structure of the BAPI must be mapped onto the fields of the BAPI interface before the BAPI is called. You can generate function modules which help to automatically convert and map the data. You can use the generated function modules in the source code of your BAPI for: •

Mapping the internal working structures of the BAPI onto the external BAPI structures before the BAPI is called

•

Mapping the result onto the internal structures after the BAPI call

•

When implementing the BAPI, mapping the inbound parameters onto the internal structure (structuring import parameters)

•

When implementing the BAPI, mapping the result from the internal structure onto the BAPI (structuring export parameters)

Features The function modules generated have the following functions: •

They map between German and English field names

•

They convert ISO codes

•

They convert currency amounts into the required internal or external format

•

They convert internal and external keys such as those used by the PSP Element (Project structure plan)

Any problems that could arise during data conversions are reported back using the RETURN parameter. Limitations Occasionally you may have to manually edit the source code of a function module after it has been automatically generated. Existing function modules can not yet be regenerated with this transaction. To regenerate an existing function module you have to manually delete the function module and then generate it anew.

Activities To generate the required function modules see Converting between Internal and External Data Formats. The Application Example illustrates the use of these function modules.

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1 23

Converting Between Internal and External Data Formats

Prerequisites Before you can generate the function modules to map between the internal working structures and the external BAPI structures, you must make sure that the internal and external structures exist.

Step by Step Procedure To generate the function module follow the steps below: 1.

Select Tools → Business Framework → BAPI Development → Generate module to map fields.

2.

In the appropriate input fields enter the names of the external BAPI structure and the internal working structure you are making the conversion between. Specify the required direction for mapping, i.e. is the internal structure to be mapped onto the external structure or vice versa.

3.

Select Function module → Generate A dialog box is displayed in which you can enter details of the function module to be generated. The input fields for the name of the function module and the short text contain suggested values which you can accept or change. In the field Function group enter the name of the function group to which the generated function module is to be added. In addition to the source text for the function module you can have a blank FORM routine added for your own program code if you have to make manual modifications. To do this, select Form to edit. The FORM routine contains the same parameters as the generated function module.

4.

Select Continue. A table is displayed containing suggestions for the conversion of each field of the external BAPI structure. The table contains the following columns: - Status Indicates if the conversion is possible or if data is missing. - Field in external structure Contains the field names of the external BAPI structure. - Conv. type Displays the conversion type. - Field in internal structure Displays the fields of the internal structure to which/from which mapping is to be carried out. For further information select F1 help for columns Status and Conv. type.

5.

To generate the function module, select Save.

Result The function module is stored in the Function Builder in the function group you specified. You can incorporate it into the source code of your BAPI as required.

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Application Example The BAPI used in this fictitious example can read the standard price of a material: bapi_material_get_price importing material like mara-matnr exporting material_price like bapi_material_price. The external structure bapi_material_price contains the fields: Fields in the external BAPI structure Field

Description

Data element

Domain

currency_iso

ISO currency code

isocd

Isocd

currency

Currency code

waers

waers

amount

Amount

bapimatprice

bapicurr

The application programmer in the R/3 System who intends to use this BAPI uses the internal structure mat_preis in his or her own program. This structure consists of the following fields: Fields in the internal working structure Field matnr

Description Material number

Data element matnr

Domain matnr

waers

Currency code

waers

waers

stprs

Unit price

stprs

strps

The BAPI structure bapi_material_price contains an ISO currency code and a currency amount. After invoking the BAPI the application programmer must convert these fields into the internal format used in R/3 in order to be able to process the fields. Using the function Generate module to map fields, the application developer can generate the function module, map2i_bapi_material_price_to_mat_preis, which converts the currency and amount fields. This function module has the following interface: function map2i_bapi_material_price_to_mat_preis importing external structure bapi_material_price changing internal structure mat_preis exceptions error_during_iso_convertion error_converting_currency_amount. The application code could be as follows: ... data: matnr like mara-matnr, preis like mat_preis, bapi_preis like bapi_material_preis. ...

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*

Call BAPI

call function bapi_material_get_price exporting material = matnr changing material_price = bapi_preis. *

Map and convert the result to internal format

call function map2i_bapi_material_price_to_mat_preis exporting external = bapi_preis changing internal = preis. *

exceptions

*

error_during_iso_convertion

*

error_during_currency_amount_conversion

preis-matnr = matnr.

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1 23

Defining Methods in the BOR Using the BOR/BAPI Wizard

Prerequisites If the function module which your BAPI is based on has been fully implemented you can define it as a method of an SAP Business Object in the Business Object Repository (BOR). You use the BOR/BAPI-Wizard to do this.

Step by Step Procedure First find the relevant SAP Business Object in the BOR: 1.

Select Tools → Business Framework → BAPI Development → Business Object Builder. On the initial Business Object Builder screen you can directly access the SAP Business Object if you know the technical name of the object (object type). You have already identified the technical name in Defining a BAPI and Its Interface. Otherwise select Business Object Repository. In the next dialog box indicate whether you want to display all object types or only business objects. Then select Continue. The application hierarchy is displayed. Select the required SAP Business Object in the application hierarchy and open it.

2. When the relevant SAP Business Object is displayed, select Change. To define your BAPI as a method of the Business Object: 1. Select Utilities → API Methods → Add method. 2. In the next dialog box enter the name of the function module, for example, BAPI_CREDITOR_GETDETAIL and select Continue. 3. In the next dialog box specify the following information for the method to be defined: -

Method A default name for the method is provided, based on the name of the function module. You will have to modify the suggested name. Delete the prefix BAPI and the business object name, so that only the method name is left. Begin every new word of the method name with a capital letter and do not use underscores. Example: If the name of the function module is BAPI_SALESORDER_GETSTATUS, the suggested method name might be BapiSalesorderGetstatus. You should edit this so that the resulting name is GetStatus.

-

Texts Enter meaningful descriptions for your BAPI.

-

Radio buttons Dialog, Synchronous, Instance-independent Enter relevant details for your BAPI. Make sure that a BAPI is not dialog orientated. BAPIs are usually implemented synchronously.

4. Select Next Step. A list of parameters and default names is displayed which you need to edit as required. Make sure that the parameter names of the method in the BOR are identical to the parameter names in the function module. Each new word in the parameter name must start with a capital letter.

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Also specify whether the individual table parameters are used for data import or data export. Table parameters are marked with a tick in the column 'MLine' (multiple lines). 5. Select Next Step. To create the method select Yes in the next dialog box.

Result After the program has been generated and executed, check that all the definitions have been made correctly by the BOR/BAPI Wizard. To do this look at the method in the BOR.

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Example of a Function Module This example function module implements the BAPI CompanyCode.GetDetail of the SAP Business Object CompanyCode (BUS0002). The BAPI CompanyCode.GetDetail reads details of a company code. Note the following in the source code: •

The name of the function module is in the format: BAPI__.

•

Specific BAPI data structures are used, identified by the prefix BAPI.

•

The key field parameter "COMPANYCODEID" is defined as the import parameter.

•

The function module performs authorization checks.

•

The function module covers all exceptions.

Source Code: function bapi_companycode_getdetail. *"-----------------------------------------------------*"*"Local interface: *" IMPORTING *" VALUE(COMPANYCODEID) LIKE BAPI0002_2-COMP_CODE *" EXPORTING *" VALUE(COMPANYCODE_DETAIL) LIKE BAPI0002_2 *" STRUCTURE BAPI0002_2 *" VALUE(COMPANYCODE_ADDRESS) LIKE BAPI0002_3 *" STRUCTURE BAPI0002_3 *" VALUE(RETURN) LIKE BAPIRETURN *" STRUCTURE BAPIRETURN *"-----------------------------------------------------... * authority check: S_TABU_DIS V_T001 perform check_authority_t001 changing return. check return is initial. * company code call function 'FI_COMPANY_CODE_DATA' exporting i_bukrs = companycodeid importing e_t001 = t001 exceptions error_message = 1 others = 0. if sy-subrc ne 0. perform set_return using '10' changing return. endif. check return-code is initial. ... endfunction.

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Testing the BAPI Purpose After you have implemented the function module your BAPI is based on and you have defined the BAPI as an SAP Business Object method in the Business Object Repository (BOR) you should check that the BAPI functions properly.

Prerequisites Carry out the test together with persons responsible for quality control in your development group. Before you start testing make sure that the underlying function module has been completely implemented and that the BAPI has been correctly defined in the BOR as a Business Object method.

Process Flow You can test the BAPI in the following ways: •

By calling the underlying function module You can individually test the function module in the Function Builder. You can enter the appropriate test values in the parameters of your function module and by running the test you can verify that the source code in the function module is processed without errors.

•

Testing the BAPI in the BOR You can test the BAPI by testing the individual method of the Business Object in the Business Object Builder. You need to know the technical name of the Business Object (object type) that you have already specified in Defining a BAPI and Its Interface. Call the Business Object Builder by selecting Tools → Business Framework → BAPI Development → Business Object Builder. Specify the appropriate object type and then start running the test by selecting Test. To test the BAPI implementation, you need to specify appropriate test values in the parameters of the BAPI. Note that for an instance-dependent BAPI you have to first specify an instance before you can run the BAPI test. Select Create instance and specify the required instance.

•

By calling the BAPI in a Visual Basic program If possible write a program in Visual Basic to call the BAPI.

•

-

Check that the BAPI can be called by BAPI ActiveX Control.

-

Check that the BAPI can be called by making RFC calls to the underlying function module.

Check the availability of documentation in the different logon languages.

Result If you find any errors in the BAPI implementation, correct them and repeat the tests until you and the quality control team in your group are fully satisfied with the BAPI implementation.

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1 23

Releasing and Freezing the BAPI

After you have completed the function module and BAPI tests and you are satisfied that they function properly, the implementation is complete. You can now release the function module the BAPI is based on and the method in the Business Object Repository (BOR), and freeze the BAPI as a method in the BOR. Once the BAPI has been released and frozen, it becomes available as a fully implemented Business Object method. Releasing and freezing also prevents anyone making incompatible changes to the BAPI, because all changes made to a released and frozen BAPI are automatically checked for compatibility in the BOR and the ABAP Dictionary, and incompatible changes are rejected. For more information about what to look out for when making changes to existing BAPIs see Enhancements to Existing BAPIs. Releasing and freezing the BAPI should be done in cooperation with the persons responsible for the development objects involved and those responsible for quality control. To release and freeze a BAPI follow the steps below: •

First release the function module in the Function Builder. Select Function module → Release → Release.

•

Set the status of the method to 'released' in the Business Object Builder. Select the relevant SAP Business Object in the Business Object Builder and expand the node Methods. Place the cursor on your BAPI and select Edit → Change status → Released.

•

Freeze the method. Place the cursor again on your BAPI in the Business Object Builder and select Utilities → API methods → Freeze method.

Check the new status of the function module in the Function Builder and the method in the BOR.

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Programming BAPIs Use This section describes how to program the BAPI you defined in the previous sections. It is not easy to formalize the functional scope of a BAPI. Every BAPI has a different functional content, even those that perform similar functions, such as the frequently used BAPIs. The differences are mainly due to the different characteristics and contents of SAP Business Objects.

Prerequisites To ensure that BAPIs, as interfaces of SAP Business Objects, provide access to R/3 data and processes in a consistent way, you must follow certain rules when programming BAPIs. These are: Mandatory Rules •

A BAPI must not contain any dialogs; in other words, the BAPI must not return any R/3 screen dialogs to the calling application. This is true for the BAPI itself and for any function module that may be indirectly called by the BAPI.

•

BAPIs must not produce any screen output, for example, display a list on the screen.

•

Database changes can only be made through updates.

•

Set and Get parameters and the global memory must not be used to transfer values.

•

If required every BAPI must be able to carry out its own authorization checks.

Recommendations •

Minimize interface complexity. Use the object/method model when choosing parameters and combining them in structures. In other words, select the most important parameters and combine them in structures in a meaningful way.

•

Application servers might not support ASCII, but use a different character set instead. If this is the case a problem may arise when you select quantities or ranges or when these are sorted. Because of this a BAPI should always select a range between A-Z, a-z and 0-9.

Other Features Also pay attention to the following when you program BAPIs: •

Programming Change BAPIs

•

Programming Replicate/Clone BAPIs

•

Programming Value Ranges

•

Internal and External Data Formats

•

Reporting Errors

•

Providing Input Help (F4 Help)

•

Improving the Performance of your BAPI

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Programming Change BAPIs Use The BAPI Change modifies an existing instance of a SAP Business Object, for example, one specific purchase order. As the Change BAPI can carry out changes to existing data, a Change BAPI must be able to identify fields that have been modified and fields that have stayed the same. Using an initial value is no solution because an initial value could also represent a valid new value. Moreover, in the ABAP programming language or on other development platforms you cannot assign the value "null" to all data types in order to mark fields and thus indicate that the remaining fields contain update values.

Features Two different approaches can be used to identify fields containing values that have been modified in a Change BAPI: •

Flagging fields to identify those fields containing modified values

•

Comparing fields to identify those fields containing modified values

1. Flagging Fields to Identify Those Fields Containing Modified Values In this approach parameter fields containing modified values are identified by a suitable flag in an additional "change parameter". •

An additional change parameter must be created with the same number of fields and the same field names for every parameter in the BAPI containing modified field values.

•

When the BAPI is called, the fields in the additional change parameter whose counterparts in the corresponding parameter contain modifications, must be marked with an update flag.

That way the BAPI can identify both modified and unmodified fields in the parameter. Follow the conventions below when you create change parameters to identify modified fields: •

The name of the additional change parameter consists of the parameter name with the suffix "X". For instance, if the parameter is called EquiSales, the name of the additional change parameter is EquiSalesX.

•

The additional change parameter must contain exactly the same number of fields and the same field names as the parameter. You must use the data element BAPIUPDATE as the data element for the update fields. This can have the following values: -

'X' This value means that the corresponding parameter field contains a modified value.

-

' ' (no value) This means that the corresponding parameter field does not have to be updated.

•

If the parameter is a table, the additional change parameter must also be a table.

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Example

A Change BAPI is used to change the value of the existing distribution channel (Distr_Chan) to Distr_Chan="US". The program objects in the R/3 System affected by this change are: Program Object SAP Business Object BAPI

Name PieceOfEquipment Change

Parameter Fields in parameter EquiSales

EquiSales SalesOrg='abcd' Distr_Chan='US' Division='efgh'

Change parameter that identifies modified fields Fields in parameter EquiSalesX

EquiSalesX SalesOrg=' ' Distr_Chan='X' Division=' '

In the parameter EquiSalesX the value in the field Distr_Chan is 'X'. This indicates that the field Distr_Chan of the parameter EquiSales contains a modified value. The BAPI Change then overwrites the existing value in the field Distr_Chan with the current value in the field Distr_Chan in the parameter EquiSales. 2. Comparing Fields to Identify Those Fields Containing Modified Values In this approach parameter fields containing modified values are identified by comparing them with the fields in an additional "compare parameter": •

An additional compare parameter must be created with the same structure for each BAPI parameter containing update values.

•

When the Change BAPI is called all relevant fields in the compare parameter must be filled with the data at the time the database is read. This data could be, for example, the result of a previous GetDetail BAPI call. The fields of the corresponding parameter may contain modified values.

•

The data in the compare parameter can first be checked against the current database contents to ascertain whether it has changed in the meantime. This way any database changes made between the time the data was read and the time the database is updated can be identified.

•

Then, the data in the compare parameter can be compared field by field with the data in the corresponding parameter. If data in any field is different then the field contains data that must be changed.

When you create compare parameters follow these conventions: •

The name of the additional compare parameter consists of the parameter name with the suffix "X". For instance, if the parameter is called EquiSales, the name of the additional compare parameter is EquiSalesX.

•

The additional compare parameter must contain exactly the same fields and the same structure as the parameter.

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Advantages of Both Approaches The advantages of each approach are shown in the table below: Area

Advantage

Performance

Approach 1: Flag table can be compressed. Compare data does not have to be read.

Programming

Approach 2: BAPI programming is simpler.

Check facilities

Approach 2: Can carry out check against current database to identify and prevent inconsistencies.

Comprehension

Approach 1: Fields containing modifications can be flagged, that means, less demands are placed on caller.

Application

Approach 1: Better for performance critical applications. Approach 2: Better for dialog-orientated applications with critical data.

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Programming Replicate/Clone BAPIs Use To replicate a business object you can implement Replicate/Clone BAPIs. The interface of these BAPIs depends on the characteristics and contents of the business object that is to be cloned. For this reason these BAPIs must be implemented for each business object. The objective of replication is to make specific instances of a business object available on one or more additional systems. The cloned business objects are created under the same object key. Business objects can be cloned in two ways: •

By request ("Pull") System "A" requests clones from system "B". Then system "B" replicates the requested business objects on system "A".

•

Using subscription lists ("Push") System "B" maintains a list of systems requiring clones. At regular intervals system "B" replicates the business objects on all the systems in the list.

Features Both of the above cloning methods can be implemented with the following BAPIs: •

Replicate A client system uses the Replicate BAPI to request clones of business objects from a server system. This method must be implemented for each business object to be cloned. The BAPI's import parameters have to identify the business objects to be cloned. You can do this by using a range table for the key fields of the business object. You can also add other import parameters, for example, to request all the materials belonging to a material group or to delimit the amount of data in the business object to be cloned (for example, material with or without plant data). Each Replicate BAPI must contain the parameter CloneReceivers which specifies the systems on which the business objects are to be replicated. Only create the Parameter RETURN as an export parameter. The BAPI Replicate requests the replication of a business object. The actual replication is carried out when the server system invokes one of the Clone BAPIs described below on the client system. You can specify whether the replication is carried out immediately or at a later time and in a separate step, depending on what is most practical for the business object.

Moreover, at least one of the BAPIs below must be implemented for each business object to be cloned. You should decide to implement one of these BAPIs, depending on the specific requirements of your BAPI: •

Clone The BAPI Clone is used by a system to replicate one business object on another system or to modify one business object that has already been cloned. All the data required for cloning an individual business object must be provided in the import parameters. Each Clone BAPI must contain the import parameter Sender which identifies the system that sends or owns the business object. If only parts of an object are to be cloned rather than the whole object, you can use other optional import parameters. Only create the Parameter RETURN as an export parameter.

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This BAPI should be used for more complex objects that will not be cloned in large numbers. •

CloneMultiple The BAPI CloneMultiple is used by a system to replicate several business objects on another system or to modify several business objects that have already been cloned. Unlike the BAPI Clone, the BAPI CloneMultiple can clone or modify several instances of an object at the same time. All the relevant data for cloning several business objects must be provided in the import parameters. Each CloneMultiple BAPI must contain the import parameter Sender which identifies the system that sends or owns the business objects. If only parts of objects are to be cloned rather than whole objects, you can use other optional import parameters. Only create the Parameter RETURN as an export parameter. This BAPI should be used for objects with small amounts of data. Although the BAPI CloneMultiple is more efficient than the BAPI Clone, it does require a far more complex interface and error handling process.

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Programming Value Ranges Use The parameters in BAPIs that can be used to search for specific instances of a business object, for example, BAPI CustomerCode.GetList, have to enable BAPI users to specify appropriate selection criteria.

Prerequisites To enable the use of selection criteria you have to create the relevant selection parameters of the BAPI as a structure or table with the following fields: Fields for Value Ranges Field Name

Description

Data element

SIGN

Selection operator that determines whether the range specified is to be included or excluded.

BAPISIGN

OPTION

Compare operator, e.g. CP (contains pattern) or BAPIOPTION NP (does not contain pattern)

LOW

Lower limit of value range

Application specific, e.g. MATNR

HIGH

Upper limit of value range

Application specific, e.g. MATNR

You can use the function module BALW_RANGES_CHECK to check the values entered in SIGN and OPTION.

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Internal and External Data Formats Use BAPIs are programming interfaces used in the most diverse application areas, for instance, to connect non-SAP systems or PC products to the R/3 System. To meet the requirements of this diverse range of applications, a shared strategy for representing data in the BAPI interface must be used. In particular, the use of values that affect Customizing or are language dependent must be avoided. BAPIs are programming interfaces, not application interfaces. Fields such as a date field, should not be used in the BAPI interface in any other format than the format used in the database, i.e. YYYYMMDD, where YYYY is the year, MM the month and DD the day. Exceptions Because of the reasons above, BAPIs should only carry out data conversions between the data format used in the database and external formats used by the calling program in exceptional circumstances. These exceptions are listed below. To convert data formats in these exceptional circumstances, you can use the transaction described in Converting Between Internal and External Data Formats. These exceptions are: •

Currency amount fields In an R/3 System a currency amount field is only useful when a currency code accompanies it, so that the decimal point in the amounts can be set correctly. Accordingly, a field for the currency code must be assigned to each currency amount field. For example, if two Yen are stored in the field of data type CURR as 0.02, a non-SAP system cannot reasonably be expected to understand these semantics. All R/3 currency data types have two digits after the decimal point, even though currencies do exist with three digits after the decimal point. For these reasons, the data type CURR cannot be used in the BAPI interface. Adhere to the following guidelines when using currency amount fields in BAPIs: -

You must not use parameters and fields of data type CURR in the interface

-

All parameters and fields for currency amounts must use the domain BAPICURR

-

The position of the decimal point in currency amount fields must be converted correctly You can use two function modules for this conversion. The function module BAPI_CURRENCY_CONV_TO_EXTERNAL converts currency amounts from R/3 internal data formats into external data formats. The function module BAPI_CURRENCY_CONV_TO_INTERNAL converts currency amounts from external data formats into internal data formats.

•

Quantity fields Like currency amount fields, the decimal point in quantity fields must be converted correctly. A unit of measure field must be assigned to every quantity field. Quantity fields have no general domain that can be used for BAPI structures.

•

Internal keys In some situations an internal technical key is maintained in the database alongside the external key. Examples are work breakdown structure plans or networks in project systems.

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You must always use the external key in the BAPI interface. •

ISO codes In R/3 Systems ISO codes are currently supported for language, country, currency, and unit of measure fields. If you use one or more of these fields in your BAPI you have to make two fields available for each of these fields in the BAPI interface: one field containing the SAP code and another containing its corresponding ISO code. Use the naming convention, Fieldname_for_SAPCode_ISO for the field containing the ISO code. For example, the field LANGU contains the country codes used internally in R/3, for instance E. The corresponding field for the ISO code would then be named LANGU_ISO and would contain the corresponding ISO code EN. Implement the BAPI as follows: -

When you export data from the BAPI both fields must contain corresponding values.

-

When you import data into the BAPI the ISO code is only significant if no value was given in the SAP code.

Use the domains below for the ISO codes: Domains for SAP internal codes and ISO codes Size

ISO Code Domain

SAP Code Domain

Currency key

isocd

waers

Unit of measure

isocd_unit

meins

Language key

laiso

spras

Country key

intca

land1

For every domain there is a data element of the same name. BAPIs for Converting Between Internal and External Data Formats (Converting Domains) BAPIs are programming interfaces in which, with a few exceptions, only the internal data format should be used. However, application programmers calling a BAPI from within their program may sometimes require the external format, for example, to display data on the screen. In such cases the calling program must be able to convert between the internal and external data formats. The following conversion BAPIs exist for this purpose. The calling program uses them to obtain the required data formats: •

BapiService.DataConversionInt2Ext This BAPI converts the internal data format into the required external data format.

•

BapiService.DataConversionExt2Int This BAPI converts the external data format into the required internal data format.

Conversion routines are maintained in the ABAP Dictionary for the domains on which the data to be converted are based. If this is not the case, no conversion takes place and the values are returned unconverted.

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Reporting Errors Use A BAPI should be able to record and classify all possible errors that may occur. You have to create a parameter named RETURN for every BAPI. This parameter returns exception messages or success messages to the calling program. All error messages or indeed any message that may be returned by the BAPI must be defined in table T100. A general error message has to be sent for those error situations that cannot sufficiently be identified and distinguished. This message can then be processed by the calling program in a different program branch. The parameter RETURN can either be implemented as an export parameter and thus as a structure, or as a table parameter. Before filling the RETURN parameter you should either initialize the structure with CLEAR or the table with REFRESH and CLEAR. If the RETURN parameter is not set or is set to an initial value this means that an error has occurred. Caution

From Release 4.0 you must not use Exceptions in a BAPI interface.

Features The structure of the parameter RETURN is dependent on the R/3 Release the BAPI is developed for. Return parameter in Release 3.1 In Release 3.1 the Return parameter is based on the structure BAPIRETURN, whose components are described in the table below. In this Release the Return parameter is filled by the function module BALW_BAPIRETURN_GET. Structure of BAPIRETURN Field TYPE

Type CHAR 1

Description

CODE

CHAR 5

The first two characters are used for the message class and the remaining ones for the message number (key fields from table T100).

MESSAGE

CHAR 220

Full message text from table T100. All variables have been replaced with text.

LOG_NO

CHAR 20

Number of application log. This is empty if no log used.

LOG_MSG_NO

NUMC 6

Current number of message in application log.

S = success message E = error message W = warning message I = information message A = termination message (Abort)

Return Parameter from Release 4.0 onwards From Release 4.0 the return parameter must be based on one of the two reference structures described below.

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Both structures take into account the name space extension of the message ID made in Release 4.0. However, if you want messages to be compatible with earlier R/3 Releases, use only the first two characters of the message ID. Both structures must be filled in the logon language. The two structures are: •

BAPIRETURN1 This structure is filled via the function module BALW_BAPIRETURN_GET1. It contains the following fields:

Field

Type

Description

TYPE

CHAR 1

S = success message E = error message W = warning message I = information message A = termination message (abort)

ID

CHAR 20

Message ID

NUMBER

NUMC 3

Message number

MESSAGE

CHAR 220

Full message text from table T100. All variables have been replaced with text

LOG_NO

CHAR 20

Number of application log. This is empty if no log is used

LOG_MSG_NO

NUMC 6

Current number of message in application log

•

BAPIRET2 This reference structure contains the additional fields PARAMETER, ROW and FIELD in which error messages can be assigned to a specific field. If a BAPI ascertains that an invalid value has been entered in a field, it can identify the field containing this value in the returned error message using the additional fields in the structure BAPIRET2. Only use this structure if you need the functionality of the additional fields to minimize the complexity of the parameter. The structure BAPIRET2 is filled via the function module BALW_BAPIRETURN_GET2. It contains the following fields:

Field

Type

Description

TYPE

CHAR 1

S = success message E = error message W = warning message I = information message A = termination message (abort)

ID

CHAR 20

Message ID

NUMBER

NUMC 3

Message number

MESSAGE

CHAR 220

Full message text from table T100. All variables have been replaced with text

LOG_NO

CHAR 20

Number of application log. This is empty if no log is used

LOG_MSG_NO

NUMC 6

Current number of message in application log

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PARAMETER

CHAR 32

Identifies the parameter containing the invalid value

ROW

INT 4

Identifies the line number of the data record containing the invalid value

FIELD

CHAR 30

Identifies the field containing the invalid value

Application Log and Application Error Tables If the information provided in the Return parameter is not sufficient, you can log errors with the application log. The logging should be done by the BAPI itself so that function modules called directly by this BAPI do not have to be modified. If this still does not provide enough information, the calling application can define its own additional error tables. There are no set guidelines for these additional tables. The Return parameter in your BAPI could give details of the messages in the error tables, for example, if there are error messages (type E) in the table. The calling program then has immediate control over the contents of the error table and does not have to first search for error messages. The use of the application log and/or error tables is optional.

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Providing Input Help (F4 Help) Use Users of an R/3 System can use the F4 key to obtain information about the possible input values for a certain field on the screen. Information about the possible input values for a field should also be available to those users who are working with the data in the R/3 System from an external program, via BAPI calls. For example, the user of a Visual Basic program which incorporates a BAPI to display or modify data in R/3 should have transparent access to the functionality of the F4 input help. In order to provide input help for a field, a calling program can use the method HelpValues.GetList. This method is based on the RFC-capable function module BAPI_HELPVALUES_GET, which obtains the possible input values for a field that is passed in a BAPI call. Detailed information about the structure and use of the HelpValues.GetList method is available in the documentation for the function module BAPI_HELPVALUES_GET.

Features In order to enable the HelpValues.GetList method to obtain the valid input values for a field in your BAPI and return them to the calling program, you must create or specify the appropriate check table, matchcodes or domain fixed values for that field in the field's reference structure. For information about check tables, matchcodes and domain fixed values see the ABAP Dictionary. This is necessary because the HelpValues.GetList method refers to the help view for the check table, matchcodes or domain fixed values linked to the field in the ABAP Dictionary. Note

Whenever possible, you should therefore specify the appropriate check table, matchcodes or domain fixed values in the reference structure of a field in order to enable a calling program to access the valid input values for the field. Authorization Check In some situations it will be necessary to only allow those persons with a particular user profile to access to information in F4 possible entries. To do this you can carry out authorization checks within your BAPI: Table BAPIF4T is provided for this purpose. This table comprises the following fields which you have to fill with the corresponding entries of your BAPI. •

OBJTYPE (object type) The technical name of the SAP Business Object, for example, BUS1065.

•

METHOD (verb) The name of a BAPI for the Business Object named above, for example, GetList.

•

DTEL (data element) The name of a data element for which a possible entry is specified. For example, an elementary input help could be specified for the data element PERNR_D and be protected from unauthorized access.

•

FNAM (name of function module) The name of the function module you have to create and that carries out the authorization check for the data element. This function module must have the following predefined interface:

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*"------------------------------------------------------*"*"Local interface: *" IMPORTING *" VALUE(OBJTYPE) LIKE BAPIF4F-OBJTYPE *" VALUE(METHOD) LIKE BAPIF4F-METHOD *" VALUE(DTEL) LIKE BAPIF4F-DTEL *" VALUE(SHLPNAME) LIKE BAPIF4F-SHLPNAME *" VALUE(TABNAME) LIKE BAPIF4F-TABNAME *" EXPORTING *" VALUE(RETURN) LIKE BAPIF4F-RETURN *"---------------------------------------------------------

As the template for your function module you can use the function module BF_BAPI_F4_AUTHORITY which provides exactly this interface. Copy this function module and follow the documentation provided with it. The additional parameter SHLPNAME contained in the function module interface provides the name of the active input help for the table or for the data element. The parameter TABNAME contains the name of the value table. The return code of the parameter RETURN is: -

'X' if the user of the BAPI is not authorized to call up the valid input values for a field.

-

' ' (no value) if the user of the BAPI is authorized to display the input values for a field.

During runtime the function module is called dynamically by the BAPI HelpValues.GetList. An authorization check can be carried out at Business Object, method or data element level: To carry out authorization check at this ...the following fields in table BAPIF4T must level... be filled. Business Object

OBJTYPE, FNAM

BAPI

OBJTYPE, METHOD, FNAM

Data element

OBJTYPE, METHOD, DTEL, FNAM

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Improving the Performance of your BAPI Use In order to improve the performance of your BAPI, you should adhere to the general guidelines of ABAP programming, such as: •

Use only complete WHERE conditions to minimize the amount of data to be transferred.

•

Avoid unnecessary database access.

•

Do make use of arrays.

•

Buffer data, for example in the local memory of the function module. Note that you must not buffer data in the global memory.

•

Try not to lock entire development objects; if possible, lock only parts of a development object.

•

Do not generate programs at runtime.

Additional guidelines for BAPI programming The function module on which a BAPI is based can be accessed by external programs via RFC. For this reason, you should follow these additional guidelines when programming BAPIs: •

Large amounts of data Mass data is treated differently in ABAP programs, which use the SAPgui (graphical user interface) as a front end, and in programs developed on external development platforms such as Visual Basic. If large amounts of data are read in the R/3 System, for example a list containing many entries, the majority of the data remains on the application server. Only the data that is actually displayed is sent to the front end. In contrast, on a Visual Basic platform, the entire data is transferred to the client system from the application server, resulting in a heavy network load and increased memory requirements on the part of the client system. You need to cover the situation when your BAPI has to read mass data. For example, you could specify a limit so that only the first n data records are read, or your BAPI could return a message to the calling programm indicating that the amount of data has exceeded a certain limit and that a new selection should be made.

•

Do not define parallel processes.

•

Make use of buffers when assigning numbers to reduce lock periods.

•

Minimize the duration of database locks by making updates after inserts. In contrast to updates, inserts do not lock the database.

•

You can reduce the duration of database locks and the risk of blocking other processes by making database updates as close as possible to the commit work command.

•

The less specific the key of a modified data record is, the more likely it is that the data record will be accessed by multiple BAPIs, causing the record to be locked. For example, running a statistic on plant level will have a negative impact on the performance of the BAPI, whereas a statistic based on plant and material will cause fewer locks because it will apply to fewer BAPIs.

•

Minimize the use of read transactions which depend on a previous database commit (committed read). These read transactions have to wait for the commit work command of the update transaction to be processed.

•

Ensure that you have chosen the correct order of the update modules.

•

All tables that are not protected by SAP internal locks must always be updated in the same order to prevent a deadlock.

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Enhancements to Existing BAPIs Purpose Application developers who are using BAPIs in their application programs must be able to rely on the fact that the BAPI's interface is not going to change. As a result of this, once a BAPI is released and frozen, it must fulfill certain requirements as to the stability of its interface. If you continue developing your BAPI after you have released and frozen it, you need to ensure that any syntax changes or changes to the contents or functionality of the BAPI are upward and downward compatible. Examples of syntax changes are changes to parameter names, or changes to the type or length of a domain. Whereas the compatibility of syntax changes is automatically checked by the ABAP Dictionary, the compatibility of changes to the contents or functional scope of a BAPI can only be safeguarded by the person developing the BAPI. Note

Enhancements to BAPIs only take effect when you have defined the changes in the BOR, that is, changes have been saved and generated. The BOR also provides version control for your BAPIs. You can differentiate between compatible and incompatible BAPI enhancements: Compatible Interface Enhancements Compatible interface enhancements are modifications to a BAPI which do not compromise the BAPI's upward or downward compatibility. Applications which access the BAPI are not affected by compatible interface enhancements. Compatible interface enhancements are: •

New optional parameters A parameter is considered to be optional if it can be left out completely in a BAPI call. Example

A new parameter is added to the BAPI SalesOrder.GetList which can be used as an additional selection criteria for selecting sales orders in the R/3 System. •

New optional fields, if these are added to the end of a structure A field is considered to be optional if it can be left out completely in a BAPI call. Example

An additional input field for the applicant's educational background is added to the BAPI Applicant.CreateFromData. Incompatible Interface Enhancements Changes to the contents or functionality of a BAPI often result in the introduction of new parameters without which the interface can no longer function. Often, these changes also cause existing parameters to lose their original meaning. Such modifications are considered to be incompatible, because they no longer enable the BAPI to be upward or downward compatible. Incompatible interface enhancements are: •

Changes to the field length

•

Changes to the field type

•

Inserting a field within a structure

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Deleting parameters and fields

•

Adding new mandatory fields or mandatory parameters

Process Flow When continuing the development of your BAPI, you should attempt to make compatible changes in order to limit the impact of your modifications on existing programs which use the BAPI. When adding a new import parameter, consider whether the interface would function without the parameter. If so, the new parameter can be added as a compatible interface enhancement. Otherwise you will have to make an incompatible interface enhancement, as described in this section. Procedure With Incompatible Interface Changes If it is necessary to make an incompatible change to your BAPI, you must not make this change to the existing BAPI. Instead, create an additional BAPI (or more, if required). Give the new BAPI the same name as the existing BAPI and add a number at the end of the name. This number can then be incremented should further enhancements become necessary. Example

A number of incompatible changes must be made to the BAPI SalesOrder.CreateFromData. To implement these changes, a new BAPI, SalesOrder.CreateFromData1, is created, in order to maintain the interface integrity of the existing BAPI SalesOrder.CreateFromData. If additional incompatible modifications must be made to the BAPI at a later date, yet another BAPI, SalesOrder.CreateFromData2, must be created. Do not remove the original BAPI from the Business Object Repository (BOR) once it has been superseded by an additional BAPI. Instead, you first identify this BAPI as expired and continue its support in the release in which you have introduced the new BAPI as well as in the release subsequent to that. During this time the original BAPI must remain fully functional and executable. The graphic below illustrates the expiry phase of a BAPI. BAPI Expiry Phase

The following tasks are required when a BAPI has expired: •

Identify the status of the original BAPI as 'expired' in the BOR. To do so, select the relevant SAP Business Object in the Business Object Builder and open the node Methods. Position the cursor on the BAPI and select Edit → Change status to → Expired.

•

In the BOR, document which method or methods are to be used as alternatives to the expiring BAPI.

•

Provide release notes during the entire retirement phase of the BAPI to inform your users about the changes.

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Checks in the ABAP Dictionary Syntax changes to a BAPI are automatically checked against the ABAP Dictionary: •

Incompatible changes to data elements, domains or structures that are being used by a BAPI that has been released are rejected by the ABAP Dictionary.

•

Compatible changes or changes to data elements, domains or structures of a BAPI that has not been released are accepted by the ABAP Dictionary.

This prevents unintentional and erroneous modifications to BAPI structures.

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Customer Modifications of BAPIs Purpose You can make enhancements or modifications to existing BAPIs. Before you decide to modify an SAP BAPI familiarize yourself with the general procedure for making customer enhancements to the SAP standard system. Refer to Enhancements to the SAP Standard. For further information see also "Guidelines for Modifying the SAP Standard System" in SAPnet. This section focuses specifically on customer enhancements and modifications of BAPIs rather than on customer enhancements in general.

Process Flow There are four ways the standard R/3 System can be adapted to meet customer needs: Customizing, enhancements, modifications and customers' own developments. The following sections describe how BAPIs can be adapted within the framework of each of these four ways. Customizing There are no special Customizing settings for BAPIs. Enhancements At present there are no customer exits or application-specific exits for BAPIs. Changes can be made, however, in the ABAP Dictionary. New fields can be added at the end of a BAPI interface structure. See also Enhancements to Existing BAPIs. Modifications You can modify an existing BAPI interface provided that only new optional parameters are involved. See also Enhancements to Existing BAPIs. You can also modify the BAPI source code but do follow the "Guidelines for Modifying the SAP Standard System". Keep in mind that an improved mechanism for making customer modifications of the SAP Standard System will be introduced in a later R/3 Release. For this reason SAP recommends that, for the time being you use one of the procedures described below to make modifications to a BAPI's source code so as not to change the SAP Standard System in the process: Creating a BAPI for an existing Business Object You can copy an existing BAPI and add it to an existing Business Object as a new BAPI. To do this: •

Copy the function module the BAPI is based on into the customer name space. For example, you could copy the function module BAPI_CUSTOMERCODE_GETLIST into Y_BAPI_CUSTOMERCODE_GETLIST.

•

Make the required changes to the new function module by changing the interface and the source code as required.

•

When you have changed and tested the function module and its interface you can define it as a new method of the appropriate business object, as described in Defining Methods in the BOR Using the BOR/BAPI Wizard Make sure you give the method a name taken from the customer name space. For example, if you have modified the BAPI GetList of the Business Object CustomerCode, you should define your development as the method YGetList.

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inherited by the subtype. You can then make changes to the copied method. To do this: •

Copy an existing Business Object type into the customer name space. This object type (subtype) acquires all methods of the existing object type. For example, you could copy the Business Object SalesOrder into YSalesOrder.

•

You can now change the required BAPI of the Business Object YSalesOrder by creating a new function module for the BAPI and assigning it to the method using the BOR/BAPIWizard.

Your Own Developments Using the information in these guidelines you can also create new methods for Business Objects. If you do, make sure that you have given your method in the BOR and the function module a name from the customer name space, this means the names must begin with X or Y. Follow the "Guidelines for Modifying the SAP Standard System" when creating other required development objects.

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Implementing BAPIs in ALE Scenarios Purpose Since Release 3.0 ALE (Application Link Enabling) technology has enabled data to be exchanged between individual distributed SAP Systems and non-SAP systems. In distributed environments it is particularly important that the individual systems are loosely coupled together and are independent of each other. Even if one of the systems fails, or a communications link is interrupted, the remaining systems must be able to continue to function. Loose coupling means that the individual systems for the most part communicate asynchronously with each other. For these reasons asynchronous messaging is used for data communication between the participating systems in ALE distribution scenarios. From Release 4.0 you can implement an asynchronous BAPI interface by generating an IDoc from the BAPI and using it in an appropriate ALE distribution scenario. For further information on ALE technology and using BAPIs in the context of ALE see ALE Programming. This section provides a general overview of points you should keep in mind when implementing a BAPI to exchange data asynchronously.

Process Flow When a BAPI is used to exchange data asynchronously within the context of ALE the following processes are involved: •

When the BAPI is called in the sending system, a function module fills the corresponding IDoc with the data from the BAPI call.

•

This IDoc is dispatched to the target system.

•

In the target system another function module is used to call the BAPI with the data from the IDoc.

You can use a transaction to create the additional objects required for the BAPI in this process, that is, the associated IDoc and the two function modules. This transaction is described in detail in ALE Programming.

Prerequisites Before you can implement a BAPI used to transfer data asynchronously in ALE, make sure that a BAPI of this type is actually required for the task in hand. If one of the following conditions applies then you should implement your BAPI as an asynchronous interface: •

Consistent database changes in both systems Data must be updated consistently on both the local system and on the remote system.

•

Loose coupling A synchronous interface would constitute too narrow a coupling between the client and the server system. If the connection is interrupted the client system would not be able to function properly.

•

Performance The interface is frequently used or it deals with large volumes of data. In this situation a synchronous interface cannot be used because performance would be too low.

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keep in mind the following points in addition to the usual BAPI programming guidelines: •

The BAPI must not issue a Commit Work command.

•

The BAPI Return parameter must use the reference structure BAPIRETURN1 or BAPIRET2.

•

All BAPI export parameters with the exception of the Return parameter are ignored and are not included in the IDoc that is generated.

•

After the function module which converts the IDoc into the corresponding BAPI in the receiving system has been called, status records are written for the IDoc in which messages sent in the Return parameter are logged. If the field type is filled with E (error) or A (abort) in at least one of the transferred Return parameter entries, the status 51 (application document has not been posted) is assigned to all the status records of the IDoc. Otherwise status 53 is assigned (application document posted).

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1 23

BAPI Implementation Checklist

This checklist summarizes the individual steps you need to complete when implementing a BAPI. Print this checklist and use the printout during the entire implementation phase of your BAPI. Ensure that you answer "yes" to each item on the list. BAPI Implementation Checklist OK?

Task Defining the scenario in which the BAPI will be used

Have you defined the scenario in which the BAPI is to be used?

Have you identified the SAP Business Object involved?

Have you defined the functional scope of the BAPI?

Have you defined the relationship between the BAPI you are planning to implement and other, related BAPIs?

Is the functionality to be implemented by the BAPI exclusively within the scope of the associated Business Object?

Is the BAPI assigned to the appropriate SAP Business Object?

Has there been a review of the BAPI concept and scenario?

Defining the BAPI

Have you identified the SAP Business Object in the Business Object Repository to which the BAPI will be added as a method?

Have you identified the key fields of this Business Object?

Have you defined the interface of the BAPI?

Have you included the key fields of the SAP Business Object in the BAPI interface?

Have you included a Return parameter?

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name for a new function group to be created?

Have you planned the name of the function module on which the BAPI is based, using the format BAPI__?

Defining the interface parameters in the function module

Have you defined the function module interface using only EXPORTING, IMPORTING and TABLES parameters?

Have you included the key fields of the SAP Business Object as parameters of the function module (i.e. depending on whether the BAPI is instancedependent or instance-independent)?

Have you assigned correct names to the parameters in the function module?

Do the function module parameters for the Business Object's key fields have the same name as the key fields of the Business Object in the BOR?

Is the name of each parameter in the function module a maximum of 20 characters in length?

Are the names of the parameters in the function module in English?

Have you avoided the use of abbreviations in the names of function module parameters?

Did you ensure that none of the parameters in the function module is customizing-relevant or affects system settings in any other way?

Is the interface independent of the current customizing settings of the system?

Are all IMPORTING parameters independent from each other, i.e. did you ensure that none of the parameters is derived from another?

Have you defined the formats in which the values must be transferred in the function module interface?

Are you using the Dictionary structure BAPIRETURN1 or BAPIRET2 for the Return parameter (as of Release 4.0)?

Defining the structures and fields of the function module parameters

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Have you assigned a corresponding currency code field to each field with currency amounts?

Have you assigned a field for the unit of measure to each quantity field?

Have you defined Dictionary structures for each function module parameter?

Do the names of the Dictionary structures start with BAPI?

Are these structures independent of the structures used in the R/3 application?

Have you defined the fields in the Dictionary structures?

Have you defined Help views or fixed values for the fields in order to enable your BAPI to provide input help (F4 help) for each field?

Are the field names a maximum of 10 characters in length?

Have you used English names for the fields, preferably those names that have been assigned to the corresponding data elements in the ABAP Dictionary?

Can the user of your BAPI access the values for each import field either by referring to the documentation, by obtaining input help (F4 help), or by using a GetDetail BAPI? Have you used a structure with the fields SIGN, OPTION, LOW and HIGH for the corresponding BAPI parameter that selects values (for example, Material.GetList)?

Defining the BAPI in the Business Object Repository

Have you planned the name of the method in the BOR?

Have you defined the names of the parameters in the BOR?

Are the names of the parameters a maximum of 20 characters in length?

Did you choose English names for the parameters?

Are the names of the parameters of the method in the BOR and the names of the parameters in the function module the same?

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Did you ensure that there are no underscores in the parameter names?

Did you start each new word in a method name with a capital letter?

Creating the objects in the R/3 System

Did you create the required Dictionary objects?

Did you create the function group, if required?

Did you create the function module?

Did you create the documentation for the BAPI in the Function Builder?

Did you use the program to map between internal and external data formats?

Did you write the program for your function module?

Did you use the BOR/BAPI wizard to define the BAPI as a method in the BOR?

Are the parameter names and types of the method in the BOR and of the function module in the Function Builder the same?

Documentation

Did you write appropriate documentation for the BAPI in the Function Builder?

Is the documentation complete?

Has the documentation been translated into the required languages?

Testing the BAPI

Did you test the function module using the test environment of the Function Builder?

Did you test the BAPI using the test environment of the Business Object Builder?

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Did you test the BAPI by making an RFC call to the underlying function module?

Did you test the documentation for its completeness, correctness and availability in the required logon languages?

Has the BAPI been released and frozen?

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