DECLARE @tablename VARCHAR(100), @columnname VARCHAR(100), @tab VARCHAR(100) SET @tablename='表名' SET @columnname='字段名' declare @defname varchar(100) declare @cmd varchar(100) select @defname = name FROM sysobjects so JOIN sysconstraints sc ON so.id = sc.constid WHERE object_name(so.parent_obj) = @tablename AND so.xtype = 'D' AND sc.colid = (SELECT colid FROM syscolumns WHERE id = object_id(@tablename) AND name = @columnname) select @cmd='alter table '+ @tablename+ ' drop constraint '+ @defname if @cmd is not null exec (@cmd)
SQL Server删除缺省约束
删除一列时,如果有缺省约束,得先删除约束才能删列,删除约束代码如下:
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转载自xafc2370.iteye.com/blog/2019319
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