System generated constraint names

  • I was reading the article "Beware to the System Generated Constraint Name" by Gregory A. Larsen. I am using DMO the create my tables, columns, and primary keys. Would you have an example of SQL-DMO code that assigns a constraint name instead of letting the system generate one.

    I am still getting an error from time to time on certain systems when MSDE is trying to generate a primary key constraint name. I would like to name the constraint like this: PK_tablename, but don't know where to do this in my DMO code. Thanks.

  • Give me a day or two I'll see what I can find. Kinda busy at work these days!

    Andy

    http://www.sqlservercentral.com/columnists/awarren/

  • Hi,

    I found this in the sql-dmo samples

    first create the table

    then add the primary key constraint like this

     
    
    Private Sub CreateMyTable()
    On Error GoTo ErrorHandler
    'This example illustrates table creation. Storage for large text and BLOB data in
    'the table is assigned from a non-default filegroup.

    Dim oDatabase As SQLDMO.Database
    'New table
    Dim oMyTable As New SQLDMO.Table
    'New table columns
    Dim colMyTableID As New SQLDMO.Column
    Dim colMyTableName As New SQLDMO.Column
    Dim colMyTableDescription As New SQLDMO.Column
    Dim colMyTablePicture As New SQLDMO.Column

    Dim sDatabase As String
    sDatabase = lstDatabases.SelectedItem
    If vbNo = MsgBox("Do you want to add MyTable to " & lstDatabases.SelectedItem & "." & lstTables.Text, vbYesNo) Then
    Exit Sub
    End If

    ' Get the database.
    Set oDatabase = goSQLServer.Databases(sDatabase)

    ' Populate the Column objects to define the table columns.
    colMyTableID.Name = "MyTableID"
    colMyTableID.Datatype = "int"
    colMyTableID.Identity = True
    colMyTableID.IdentityIncrement = 1
    colMyTableID.IdentitySeed = 1
    colMyTableID.AllowNulls = False

    colMyTableName.Name = "MyTableName"
    colMyTableName.Datatype = "varchar"
    colMyTableName.Length = 15
    colMyTableName.AllowNulls = False

    colMyTableDescription.Name = "MyTableDescription"
    colMyTableDescription.Datatype = "text"
    colMyTableDescription.AllowNulls = True

    colMyTablePicture.Name = "MyTablePicture"
    colMyTablePicture.Datatype = "image"
    colMyTablePicture.AllowNulls = True

    ' Name the table, then set desired properties to control eventual table
    ' construction.
    oMyTable.Name = "MyTable"
    oMyTable.FileGroup = "PRIMARY"


    ' Add populated Column objects to the Columns collection of the
    ' Table object.
    oMyTable.Columns.Add colMyTableID
    oMyTable.Columns.Add colMyTableName
    oMyTable.Columns.Add colMyTableDescription
    oMyTable.Columns.Add colMyTablePicture

    ' Create the table by adding the Table object to its containing
    ' collection.
    oDatabase.Tables.Add oMyTable
    '
    '
    'In a second step

    'Now create a PRIMARY key
    Dim keyPKMyTable As New SQLDMO.Key
    Dim namesPKMyTable As SQLDMO.Names

    ' Create the primary, clustered key on mytableid
    keyPKMyTable.Clustered = True
    keyPKMyTable.Type = SQLDMOKey_Primary
    'give constraint a name
    keyPKMyTable.Name = "pk_mytable"

    ' Use the Names collection to define the constraint on the
    Set namesPKMyTable = keyPKMyTable.KeyColumns
    namesPKMyTable.Add "MyTableID"



    ' Mark start of change unit.
    oMyTable.BeginAlter

    ' Add the populated Key object to the Keys collection of the
    ' Table object.
    oMyTable.Keys.Add keyPKMyTable

    ' Create the PRIMARY KEY constraint by committing the unit of change.
    oMyTable.DoAlter

    Exit Sub

    ErrorHandler:
    MsgBox Err.Description

    End Sub
  • Thank you SO much. It works!

    It was the line: keyPKMyTable.Name = "pk_mytable" that I was looking for! 🙂

    Where did you find the sql-dmo samples?

  • Hi , the sql-dmo samples are installed (i used the default installation location)

    in:

    C:\Program Files\Microsoft SQL Server\80\Tools\DevTools\Samples\sqldmo

    best regards,

    Klaas-Jan

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