本节内容:
用于删除数据库中存储过程、主键、外键、索引的sql语句。
以下sql语句,实现删除存储过程、默认值与约束、触发器、索引等,用来学习t-sql查询语句的编写,是个不错的实例。
例子:
--删除存储过程
DECLARE @STRING VARCHAR(8000)
WHILE EXISTS(SELECT NAME FROM SYSOBJECTS WHERE TYPE='P' AND STATUS>=0)
BEGIN
SELECT @STRING='DROP PROCEDURE '+NAME FROM SYSOBJECTS WHERE TYPE = 'P' AND STATUS>=0
--SELECT @STRING
EXEC(@STRING)
END
GO
--默认值或 DEFAULT 约束
DECLARE @STRING VARCHAR(8000)
WHILE EXISTS(SELECT NAME FROM SYSOBJECTS WHERE XTYPE='D')
BEGIN
SELECT @STRING='ALTER TABLE '+B.NAME+' DROP CONSTRAINT '+A.NAME
FROM (SELECT PARENT_OBJ,NAME FROM SYSOBJECTS WHERE XTYPE='D') A,
(SELECT ID,NAME FROM SYSOBJECTS WHERE OBJECTPROPERTY(ID, N'ISUSERTABLE') = 1) B
WHERE A.PARENT_OBJ=B.ID
EXEC(@STRING)
END
GO
--UNIQUE 约束
DECLARE @STRING VARCHAR(8000)
WHILE EXISTS(SELECT NAME FROM SYSOBJECTS WHERE XTYPE='UQ')
BEGIN
SELECT @STRING='ALTER TABLE '+B.NAME+' DROP CONSTRAINT '+A.NAME
FROM (SELECT PARENT_OBJ,NAME FROM SYSOBJECTS WHERE XTYPE='UQ') A,
(SELECT ID,NAME FROM SYSOBJECTS WHERE OBJECTPROPERTY(ID, N'ISUSERTABLE') = 1) B
WHERE A.PARENT_OBJ=B.ID
EXEC(@STRING)
END
GO
--FOREIGN KEY 约束
DECLARE @STRING VARCHAR(8000)
WHILE EXISTS(SELECT NAME FROM SYSOBJECTS WHERE TYPE='F')
BEGIN
SELECT @STRING='ALTER TABLE '+B.NAME+' DROP CONSTRAINT '+A.NAME
FROM (SELECT PARENT_OBJ,NAME FROM SYSOBJECTS WHERE TYPE='F') A,
(SELECT ID,NAME FROM SYSOBJECTS WHERE OBJECTPROPERTY(ID, N'ISUSERTABLE') = 1) B
WHERE A.PARENT_OBJ=B.ID
EXEC(@STRING)
END
GO
--PRIMARY KEY 约束
DECLARE @STRING VARCHAR(8000)
WHILE EXISTS(SELECT NAME FROM SYSOBJECTS WHERE XTYPE='PK')
BEGIN
SELECT @STRING='ALTER TABLE '+B.NAME+' DROP CONSTRAINT '+A.NAME
FROM (SELECT PARENT_OBJ,NAME FROM SYSOBJECTS WHERE XTYPE='PK') A,
(SELECT ID,NAME FROM SYSOBJECTS WHERE OBJECTPROPERTY(ID, N'ISUSERTABLE') = 1) B
WHERE A.PARENT_OBJ=B.ID
EXEC(@STRING)
END
GO
--触发器
DECLARE @STRING VARCHAR(8000)
WHILE EXISTS(SELECT NAME FROM SYSOBJECTS WHERE XTYPE='TR')
BEGIN
SELECT @STRING='DROP TRIGGER '+NAME FROM SYSOBJECTS WHERE XTYPE='TR'
EXEC(@STRING)
END
GO
--索引
declare @string varchar(8000)
while exists(
select TABLE_NAME= o.name,INDEX_NAME= x.name
from sysobjects o, sysindexes x, syscolumns c, sysindexkeys xk
where o.type in ('U')
and convert(bit,(x.status & 0x800)/0x800)=0
and x.id = o.id
and o.id = c.id
and o.id = xk.id
and x.indid = xk.indid
and c.colid = xk.colid
and xk.keyno <= x.keycnt
and permissions(o.id, c.name) <> 0
and (x.status&32) = 0 -- No hypothetical indexes
group by o.name,x.name)
begin
select top 1 @string='drop index '+o.name+'.'+ x.name
from sysobjects o, sysindexes x, syscolumns c, sysindexkeys xk
where o.type in ('U')
and convert(bit,(x.status & 0x800)/0x800)=0
and x.id = o.id
and o.id = c.id
and o.id = xk.id
and x.indid = xk.indid
and c.colid = xk.colid
and xk.keyno <= x.keycnt
and permissions(o.id, c.name) <> 0
and (x.status&32) = 0 -- No hypothetical indexes
group by o.name,x.name
exec(@string)
end
GO