Ch02_Concepts_8e_Solutions.doc

Concepts of Database Management, Eighth Edition

Solutions 2-1

Chapter 2 The Relational Model 1: Introduction, QBE, and Relational Algebra Solutions Ansers to Re!ie Questions  Note: Answers

to odd-numbered review uestions are found in Appendi! D of the te!tboo"#

1#

A rela relatio tion n is a twotwo-dim dimens ension ional al tabl tablee in whic which h $1% $1% the the entrie entriess in the the table table are are singl single-v e-valu alued& ed& $2% each each colu column mn has has a distinct name& $'% all of the values in a column are values of the same attribute& $(% the order of the columns is immaterial& $)% each row is distinct& and $*% the order of the rows is immaterial#

2#

A rela relati tion onal al data databa base se is a col colle lect ctio ion n of of rel relat atio ions ns##

'#

An unnorm unnormali ali+ed +ed rela relatio tion n is a struct structure ure that that sati satisfi sfies es all the the prope properti rties es of a relat relation ion e!ce e!cept pt the rest restric rictio tion n that that entries entries must be single-valued# t is not a relation#

(#

n the the relati relationa onall model, model, an an attrib attribute ute is is a proper propert t of an an entit entit## Attr Attribu ibute te is anot another her term term for for a colum column n in a table table## t also also is commonl called a field#

)#

n the the shorth shorthand and repr represe esenta ntatio tion, n, each each tabl tablee is list listed, ed, and afte afterr each each table table,, all the the column columnss of the the tabl tablee are are liste listed d in  parentheses# .rimar .rimar "es are underlined# underlined# /he /he shorthand representation representation for the Colonial Adventure /ours /ours database is is as follows0 Trip (TripID, TripName, StartLocation, State, Distance, MaxGrpSize, Type, Season) Guide (GuideNum, LastName, FirstName, Address, City, State, osta!Code, "oneNum, #ireDate) Customer (CustomerNum, LastName, FirstName, Address, City, State, osta!Code, "one) $eser%ation ($eser%ationID, TripID, TripDate, Numersons, Triprice &t"erFees, CustomerNum) TripGuides (TripID, GuideNum)

*#

/o ualif ualif  a field field name name means means to indic indicate ate the the table table to whic which h it belo belongs ngs b prece precedin ding g the field field name name with with the table table name and a period# /o ualif the Street field in the Customer table, ou would enter Customer#Street#

#

/he prim primar ar "e is is the column column or coll collect ection ion of colu columns mns that that uniue uniuel l ident identifi ifies es a give given n row# row# /he /he prima primar r "e "e of the the /rip table is /ripD# /ripD# /he primar "e of the uide table is uide3um# /he primar "e of the Customer table is Customer3um# Customer3um# /he primar "e of the 4eservation table is 4eservationD# /he primar "e of the /ripuides /ripuides table is the concatenation $combination% of /ripD and uide3um#

5#

nclud ncludee the the fiel field d in the design design grid grid and and ma"e ma"e sure sure the field6 field6ss Show Show chec" chec" bo! bo! cont contain ainss a chec" chec" mar mar"# "#

7#

Ente Enterr the the crit criter eria ia in the the Cri Crite teri riaa row row for for the the appr approp opri riat atee fie field ld name name##

18#

/o combine combine crite criteria ria with with A3D, A3D, enter enter the the conditio conditions ns on the same same Criter Criteria ia row row in the design design grid# /o combine combine crite criteria ria with 94, enter the conditions on different Criteria rows in the design grid#

11#

/pe the the computat computation ion inste instead ad of a field field name name in the the design design grid# grid# Alternat Alternativel ivel , ou can enter enter the the computa computation tion in in the :oom dialog bo!#

;281) Cengage