sql语句与例子

新建表：
create table [表名]
(
[自动编号字段] int IDENTITY (1,1) PRIMARY KEY ,
[字段1] nVarChar(50) default \'默认值\' null ,
[字段2] ntext null ,
[字段3] datetime,
[字段4] money null ,
[字段5] int default 0,
[字段6] Decimal (12,4) default 0,
[字段7] image null ,
)
eg.
create table test
(
id int IDENTITY (1,1) PRIMARY KEY ,
tname nVarChar(50) default null ,
intro ntext null ,
entrence datetime,
salary money null ,
age int default 0,
height Decimal (12,4) default 0,
picture image null ,
)
删除表：
Drop table [表名]
eg.
drop table test

插入数据：
INSERT INTO [表名] (字段1,字段2) VALUES (100,\'51WINDOWS.NET\')
eg.
values('080810138','范成龙','男',23,'计算机系','2008/9/1')

删除数据：
DELETE FROM [表名] WHERE [字段名]>100
delete from student where sno='080810138'

更新数据：
UPDATE [表名] SET [字段1] = 200,[字段2] = \'51WINDOWS.NET\' WHERE [字段三] = \'HAIWA\'
eg.
update student set sentrence='1989-9-1' where sno='080810138'

新增字段：
ALTER TABLE [表名] ADD [字段名] NVARCHAR (50) NULL
eg.
alter table student  add  sentrence datetime

删除字段：
ALTER TABLE [表名] DROP COLUMN [字段名]
eg.
alter table student  drop column sentrence

修改字段：
ALTER TABLE [表名] ALTER COLUMN [字段名] NVARCHAR (50) NULL
eg.
alter table student alter column  sage smallint

sp_rename \'表名\', \'新表名\', \'OBJECT\'
eg.
sp_rename 'Student','s'

新建约束：
ALTER TABLE [表名] ADD CONSTRAINT 约束名 CHECK ([约束字段] <= \'2000-1-1\')
eg.
alter table student add constraint sex check (Ssex in('男','女'))

删除约束：
ALTER TABLE [表名] DROP CONSTRAINT 约束名
eg.
alter table student drop constraint sex

新建默认值
ALTER TABLE [表名] ADD CONSTRAINT 默认值名 DEFAULT \'51WINDOWS.NET\' FOR [字段名]
eg.
alter table student add constraint sb default '男' for ssex

删除默认值
ALTER TABLE [表名] DROP CONSTRAINT 默认值名
eg.
alter table student drop constraint sb
--------------------------------------
尚未举例

删除Sql Server 中的日志，减小数据库文件大小
dump transaction 数据库名 with no_log
backup log 数据库名 with no_log
dbcc shrinkdatabase(数据库名)
exec sp_dboption \'数据库名\', \'autoshrink\', \'true\'

\\\'添加字段通用函数
Sub AddColumn(TableName,ColumnName,ColumnType)
Conn.Execute(\"Alter Table \"&TableName&\" Add \"&ColumnName&\" \"&ColumnType&\"\")
End Sub

\\\'更改字段通用函数
Sub ModColumn(TableName,ColumnName,ColumnType)
Conn.Execute(\"Alter Table \"&TableName&\" Alter Column \"&ColumnName&\" \"&ColumnType&\"\")
End Sub

\\\'检查表是否存在

sql=\"select count(*) as dida from sysobjects where id = object_id(N\'[所有者].[表名]\') and OBJECTPROPERTY(id, N\'IsUserTable\')

= 1\"

set rs=conn.execute(sql)

response.write rs(\"dida\")\'返回一个数值，0代表没有，1代表存在

判断表的存在:
select * from sysobjects where id = object_id(N\'[dbo].[tablename]\') and OBJECTPROPERTY(id, N\'IsUserTable\') = 1

某个表的结构
select * from syscolumns where id = object_id(N\'[dbo].[你的表名]\') and OBJECTPROPERTY(id, N\'IsUserTable\') = 1