This stored procedure takes table name as parameter and dynamically creates a drop script for all the constraints of given table and executes it. Earliar today I was searching scripts concerning the same but I mostly found scripts related to information schema of the database. As a small developer I thought it was risky to put a hand on that. I was able to create this simple script which just involves a cursor on sysobjects table.
CREATE PROCEDURE DeleteConstraints
@tableName VARCHAR(100)
AS
BEGIN
DECLARE @sql VARCHAR(max)
DECLARE @conName VARCHAR(100)
DECLARE @con CURSOR
SET @con = CURSOR FOR SELECT name FROM sysobjects WHERE parent_obj=(SELECT id FROM sysobjects WHERE name=@tableName) AND type IN ('C','D','F','K')
OPEN @con
FETCH NEXT
FROM @con INTO @conName
WHILE @@FETCH_STATUS = 0
BEGIN
SET @sql = 'IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N''[' + @conName + ']'') AND type IN (''C'',''D'',''F'',''K'')
BEGIN
ALTER TABLE [dbo].[' + @tableName + '] DROP CONSTRAINT [' + @conName + ']
END'
EXEC(@sql)
FETCH NEXT
FROM @con INTO @conName
END
CLOSE @con
DEALLOCATE @con
END
GO
