SQLServer的日常维护语句

1、删除外键约束，建立外键约束

先建立3个表： 

/*drop table tbdrop table tb_bdrop table tb_c*/--建立3个关联的表create table tb(id int primary key ,vv varchar(10))create table tb_b(idd int primary key,id int foreign key references tb(id))create table tb_c(iddd int primary key,idd int foreign key references tb_b(idd))go 

可以生成删除外键的语句，需要复制出来，然后放到再执行： 

;WITH FK  --外键约束AS(	SELECT		SCH.name as foreign_schema_name,   --外键schema名		FK.name as foreign_name,           --外键名		FK.is_disabled ,                   --是否禁用				FK.delete_referential_action_desc as delete_action,		FK.update_referential_action_desc as update_action,				FKC.constraint_column_id,		   --约束列的id		FKC.parent_object_id,              --父对象的id		FKC.parent_column_id,              --父对象列的id						FKC.referenced_object_id,          --被引用的对象		FKC.referenced_column_id           --被引用的对象中的列	 FROM sys.foreign_keys FK		INNER JOIN sys.foreign_key_columns FKC			ON FK.object_id = FKC.constraint_object_id		INNER JOIN sys.schemas SCH			ON FK.schema_id = SCH.schema_id),TB   --表和列AS(	SELECT 		TB.object_id,		SCH.name as schema_name,		TB.name as table_name,		C.column_id as column_id,		C.name as column_name			FROM sys.tables TB WITH(NOLOCK)		INNER JOIN sys.columns C WITH(NOLOCK)			ON TB.object_id = C.object_id		INNER JOIN sys.schemas SCH WITH(NOLOCK)			ON TB.schema_id = SCH.schema_id	WHERE TB.is_ms_shipped = 0  -- 此条件表示仅查询不是由内部 SQL Server 组件创建对象)SELECT    'alter table ['+TBP.schema_name+'].['+TBP.table_name+    '] drop constraint ['+FK.foreign_name+'];' as '删除外键的语句,复制出来后运行'FROM FKINNER JOIN TB TBP		ON FK.parent_object_id = TBP.object_id		   AND FK.parent_column_id = TBP.column_id		   INNER JOIN TB TBR		ON FK.referenced_object_id = TBR.object_id		   AND FK.referenced_column_id = TBR.column_id/*删除外键的语句,复制出来后运行alter table [dbo].[tb_b] drop constraint [FK__tb_b__id__6754599E];alter table [dbo].[tb_c] drop constraint [FK__tb_c__idd__6C190EBB];*/

;WITH FK  --外键约束AS(	SELECT		SCH.name as foreign_schema_name,   --外键schema名		FK.name as foreign_name,           --外键名		FK.is_disabled ,                   --是否禁用				FK.delete_referential_action_desc as delete_action,		FK.update_referential_action_desc as update_action,				FKC.constraint_column_id,		   --约束列的id		FKC.parent_object_id,              --父对象的id		FKC.parent_column_id,              --父对象列的id						FKC.referenced_object_id,          --被引用的对象		FKC.referenced_column_id           --被引用的对象中的列	 FROM sys.foreign_keys FK		INNER JOIN sys.foreign_key_columns FKC			ON FK.object_id = FKC.constraint_object_id		INNER JOIN sys.schemas SCH			ON FK.schema_id = SCH.schema_id),TB   --表和列AS(	SELECT 		TB.object_id,		SCH.name as schema_name,		TB.name as table_name,		C.column_id as column_id,		C.name as column_name			FROM sys.tables TB WITH(NOLOCK)		INNER JOIN sys.columns C WITH(NOLOCK)			ON TB.object_id = C.object_id		INNER JOIN sys.schemas SCH WITH(NOLOCK)			ON TB.schema_id = SCH.schema_id	WHERE TB.is_ms_shipped = 0  -- 此条件表示仅查询不是由内部 SQL Server 组件创建对象)SELECT    'alter table ['+TBP.schema_name+'].['+TBP.table_name+    '] add constraint ['+FK.foreign_name+'] '+    ' foreign key('+TBP.column_name+') references [' +    TBR.schema_name +'].['+ TBR.table_name +']('+TBR.column_name+')'    as '新建外键索引,复制然后在运行'FROM FKINNER JOIN TB TBP		ON FK.parent_object_id = TBP.object_id		   AND FK.parent_column_id = TBP.column_id		   INNER JOIN TB TBR		ON FK.referenced_object_id = TBR.object_id		   AND FK.referenced_column_id = TBR.column_id/*新建外键索引,复制然后在运行alter table [dbo].[tb_c] add constraint [FK__tb_c__idd__0A9D95DB]  foreign key(idd) references [dbo].[tb_b](idd)alter table [dbo].[tb_b] add constraint [FK__tb_b__id__05D8E0BE]  foreign key(id) references [dbo].[tb](id)*/

create table tb(id int primary key ,vv varchar(10))insert into tbvalues(1,'aa') go create table tb_b(idd int primary key,id int --foreign key references tb(id))insert into tb_bvalues(1,2)  --id不在主表中go--新增外键约束,不会报错，with nocheck对于之前已经存在的数据，不会进行检测ALTER TABLE [dbo].[tb_b]  WITH noCHECK ADD FOREIGN KEY([id])REFERENCES [dbo].[tb] ([id])GO --会报错 ，在建立上面的约束后，再次插入，就会报错了insert into tb_bvalues(2,2)  --id不在主表中

2、如何根据表名查询出创建该表的代码 

--当用以下代码创建一个表后，如何根据表名查询出创建该表的代码(也就是以下代码)？CREATE TABLE [dbo].[a1](	[c2] [decimal](10, 2) NULL,	[c3] [decimal](10, 3) NULL CONSTRAINT [DF_a1_c3]  DEFAULT ((0)),	[re] [bigint] IDENTITY(1,1) NOT NULL, CONSTRAINT [PK_a1] PRIMARY KEY CLUSTERED (	[re] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]go

declare @sql varchar(8000),@tablename varchar(100)set @tablename ='a1'--这里输入表名set @sql = 'create table ['+@tablename+'] ('select @sql = @sql + b.name + ' '+       c.name+       case when c.collation_name is not null then '('+         case when b.max_length <>-1 then convert(varchar(100),b.max_length)           else 'MAX'         end +') '        else ''       end +       case when b.is_identity = 1 then ' identity('+convert(varchar(100),IDENT_SEED(@tablename))+','+convert(varchar(100),IDENT_INCR(@tablename))+')' else '' end +       case when d.definition is not null then ' default('+d.definition +')' else '' end +       case when b.is_nullable = 0 then ' not null' else ' null' end +       ','from sys.objects a join sys.columns bon a.object_id = b.object_idjoin sys.types con b.system_type_id = c.system_type_id and b.user_type_id = c.user_type_idleft join sys.default_constraints don b.default_object_id = d.object_idwhere a.name=@tablenameorder by b.column_idif exists(select * from sys.indexes where object_id =object_id(@tablename) and is_primary_key =1 )beginselect @sql = @sql + 'CONSTRAINT ['+name+'] PRIMARY KEY '+type_desc+'(' from sys.indexes where object_id =object_id(@tablename) and is_primary_key =1select @sql = @sql + b.name + case when a.is_descending_key =1 then ' DESC' else ' ASC' end +',' from sys.index_columns a join sys.columns bon a.object_id= b.object_id and a.column_id = b.column_idwhere a.object_id =object_id(@tablename)select @sql = left(@sql,len(@sql)-3)+')'select @sql = @sql+') ON [PRIMARY] 'endelsebeginselect @sql = left(@sql,len(@sql)-1)+') ON [PRIMARY] 'endprint @sql/*create table [a1] (c2 decimal null,c3 decimal default(((0))) null,re bigint identity(1,1) not null,CONSTRAINT [PK_a1] PRIMARY KEY CLUSTERED(re ASC)) ON [PRIMARY] */