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VB.net SQL Check if Primary key is an identity column

Posted on 2013-06-25
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Last Modified: 2013-06-25
Hi

I use the following VB.net code to check if a column is a primary key.
How do I find if it is an identity column
For example "[ID] bigint identity(1,1) primary key" is an identity column
and "[ID] bigint primary key" is not an identity column


               sSQL = "SELECT column_name "
                sSQL = sSQL & "FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE "
                sSQL = sSQL & "WHERE OBJECTPROPERTY(OBJECT_ID(constraint_name), 'IsPrimaryKey') = 1"
                sSQL = sSQL & "AND table_name = '" & oTableName & "'"

                Dim connection As New SqlConnection(Globals.ThisAddIn.oRIGHT.lblConnectionString.Text)
                Dim cmd As New SqlCommand(sSQL, connection)
                connection.Open()
                Get_Primary_Key = cmd.ExecuteScalar().ToString
                connection.Close()
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Question by:Murray Brown
5 Comments
 
LVL 22

Assisted Solution

by:Om Prakash
Om Prakash earned 668 total points
ID: 39274091
Try:
SELECT name, is_identity FROM sys.columns WHERE [object_id] = object_id('table_name')

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which will list column name with is_identity column value as 1 if the column has identity
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LVL 42

Assisted Solution

by:Meir Rivkin
Meir Rivkin earned 664 total points
ID: 39274094
to check if column is mandatory, u simply check the column.AllowDBNull property:

http://msdn.microsoft.com/en-us/library/system.data.datacolumn.allowdbnull.aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2
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LVL 13

Accepted Solution

by:
Philip Pinnell earned 668 total points
ID: 39274096
You probably want something like

SELECT [IS_NULLABLE]
FROM [msdb].[INFORMATION_SCHEMA].[COLUMNS]
where [column_name] = 'myColumn'
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Author Closing Comment

by:Murray Brown
ID: 39274109
Thanks very much
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LVL 13

Expert Comment

by:Philip Pinnell
ID: 39274243
Thanks
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