Download Database Modelling with ERwin

IntroductiontoERwin
DatabaseDesign&Modelling
Hans-PetterHalvorsen,M.Sc.
Software
ThefollowingEditionscanbedownloadedforFree onInternet:
CAERwinDataModelerCommunityEdition
SQLServerExpressEdition
Overview
1.DesignandCreateTables
3.ExecutetheScriptwithinSQLServer
2.MakeaSQLScript
4.StartusingyourDatabase,
InsertData,etc.
DatabaseDesign&
Modelling
Hans-PetterHalvorsen,M.Sc.
DatabaseDesign– ERDiagram
ERDiagram(Entity-RelationshipDiagram)
• UsedforDesignandModelingofDatabases.
• SpecifyTablesandrelationship betweenthem(PrimaryKeysandForeignKeys)
Example:
TableName
TableName
Column
Names
PrimaryKey
PrimaryKey
ForeignKey
RelationalDatabase.InarelationaldatabaseallthetableshaveoneormorerelationwitheachotherusingPrimaryKeys(PK)and
ForeignKeys(FK).Note!YoucanonlyhaveonePKinatable,butyoumayhaveseveralFK’s.
Database- “BestPractice”
• Tables:Useuppercaseandsingular formintablenames– notplural,e.g.,
“STUDENT”(not“students”)
• Columns:UsePascalnotation,e.g.,“StudentId”
• PrimaryKey:
• Ifthetablenameis“COURSE”,namethePrimaryKeycolumn“CourseId”,
etc.
• “Always”useInteger andIdentity(1,1) forPrimaryKeys.UseUNIQUE
constraintforothercolumnsthatneedstobeunique,e.g.“RoomNumber”
• SpecifyRequired Columns(NOTNULL)– i.e.,whichcolumnsthatneedtohave
dataornot
• Standardizeonfew/theseDataTypes:int,float,varchar(x),datetime,bit
• UseEnglishfortableandcolumnnames
• Avoidabbreviations!(Use“RoomNumber”– not“RoomNo”,“RoomNr”,...)
DatabaseDesign&Implementation
RecommendedSteps:
1. DatabaseModelling/DesignusingERwin
2. GenerateSQLTableScriptusingERwin(youmight
needtoadjust/improveitinordertomakeitmore
robust)
3. GenerateTablesinSQLServerusingtheSQLScript
generatedbyERwin
4. CreateStoredProcedures,View,Triggers,etc.inside
SQLServerifneeded.
ERwin
Hans-PetterHalvorsen,M.Sc.
CAERwinDataModelerCommunityEdition
• ToolforDatabaseModelling(ERDiagrams)
• Free!
• ForwardandReverseEngineeringwitha25
objectlimit
Downloadhere:
http://erwin.com/products/data-modeler/community-edition
ERwinExample
NewDatabaseModel
OpenERwinandselectFile->New...
Thefollowingwindowappears(NewModel):
Makesuretoselect
Logical/PhysicalModel
SelecttheDatabaseTypeandVersionyoushalluse
PageSetup
Exercise
LetstrytocreatethefollowingTables,Columns,
PrimaryKeysandForeignKeysusingERwin:
CreateTablesandColumns
Usethe“Entity”Toolinorder
toCreateNewTables
Use<Tab>and<Enter>inordertogivethe
TablesaNameandtocreateColumns.
Usethe<Arrows>toswitchbetweenthe
ColumnsinsideaTable
CreatePrimaryKey(PK)– ForeignKey(FK)Relationships
Usethe“Relationship”ToolinordertoCreateaPrimaryKey
(PK)– ForeignKey(FK)Relationship
ClickfirstonthePKtableandthenontheFKtableusingthe“Relationship”
Tool.TheRelationshipConnectionisthenCreatedAutomatically
SetDataTypes
Makesuretoset
properDataTypes
YoumayalsoDouble-click(orRight-clickand
selectTable/ColumnProperties)onTables
andColumnsinordertochangedifferent
Attributes,eg.DataTypes,etc.
Attributes
MoreTables...
WecanextendourDatabaseDesign/Modellwith,e.g.:
• AUTHOR
• PUBLISHER
• CATEGORY(e.g.,Programming,ControlSystems,..)
...
(Youcantrythisonyourown)
CreateSQLScriptswithERwin
Hans-PetterHalvorsen,M.Sc.
CreateSQLScript
Select“ForwardEngineering”
and“Schema...”
2
1
Makesureyouareusing
thePhysicalModel
3
4
Select/DeselectdifferentOptions
inordertomakeyourscriptthe
wayyouwant.Click“Preview”in
ordertoseetheresults.
Click“Save”whenyouare
satisfiedwithyourScript
SQLServer
ExecutetheSQLScriptwithinSQLServer
Hans-PetterHalvorsen,M.Sc.
MicrosoftSQLServer
Software
MicrosoftSQLServerManagementStudio
3
YourSQLServer
1
2
YourDatabase
4
WriteyourQueryhere
Your
Tables
5 TheResultsfromyourQuery
MicrosoftSQLServer– CreateaNewDatabase
2
1
Nameyoudatabase
accordingtoyourProject
1
OpenSQLServerand
createa“NewDatabase...”
SQLServer
3
YouareFinished.Startinserting
sometestdata,etc.
2
OpentheSQLScriptinorder
toinserttheTablesinSQL
Server
Identity(1,1)
Hans-PetterHalvorsen,M.Sc.
SettingtheIdentity(1,1)
PropertyinERwin
1
2
3
Exercise
Hans-PetterHalvorsen,M.Sc.
DatabaseDesign&ModellingExercise
CreatethisExampleusingERwin.
CreateaScriptandexecuteitwithinSQLServer.
Hans-PetterHalvorsen,M.Sc.
UniversityCollegeofSoutheastNorway
www.usn.no
E-mail:[email protected]
Blog:http://home.hit.no/~hansha/