IF NOT EXISTS (SELECT * FROM SYSCOLUMNS INNER JOIN SYSOBJECTS ON SYSOBJECTS.id = SYSCOLUMNS.id 
              WHERE SYSCOLUMNS.NAME = 'SABITFIYAT' AND SYSOBJECTS.name = 'TPAKETISL')
ALTER TABLE dbo.[TPAKETISL] ADD SABITFIYAT bit NOT NULL CONSTRAINT [DF_TPAKETISL_SABITFIYAT] DEFAULT (0)
GO
