SQL语句

CREATE DATABASE test
ON PRIMARY                                --建立主数据文件
(NAME=‘test‘,
FILENAME=‘E:\MSSQL_DATA\test.mdf‘,
SIZE=5,
MAXSIZE=5,
FILEGROWTH=1)
LOG ON
(
NAME=test_log,
FILENAME=‘E:\MSSQL_LOG\test_log.ldf‘,
SIZE=1,
MAXSIZE=2,
FILEGROWTH=1
)

use test
create table teacher(
ID int Identity(1,1) not null,     --identity表示自增，从1开始每次自增1
Name varchar(20) not null,
Sex char(2) null,
Phone varchar(20) not null,
Sallary smallmoney null,
Address varchar(100) null,
Email varchar(30) null)  --可变长度，最大为255个字符

DROP DATABASE test
DROP TABLE teacher    --注意和delete的区别，delete teacher是删除表teacher中的所有数据，DROP是删除表

ALTER DATABASE test
modify name=test_t

ALTER TABLE teacher
add Subject varchar(30) null

ALTER TABLE teacher      --每次修改之前都要加一句ALTER，不能连续写2行
DROP COLUMN price

--加入组
ALTER DATABASE test
ADD FILEGROUP test_group

--连续加入2个次数据文件
ALTER DATABASE test
ADD FILE 
(NAME=test1,
FILENAME=‘E:\MSSQL_DATA\test1.ndf‘,
SIZE=5,
MAXSIZE=5,
FILEGROWTH=1),
(
NAME=test2,
FILENAME=‘E:\MSSQL_DATA\test2.ndf‘,
SIZE=5,
MAXSIZE=5,
FILEGROWTH=1
) to filegroup test_group
GO
ALTER DATABASE test
ADD LOG FILE(
NAME=testlog1,
FILENAME=‘E:\MSSQL_LOG\testlog1.ldf‘,
SIZE=1,
MAXSIZE=3,
FILEGROWTH=1)
GO

--删除数据文件和组
ALTER DATABASE test
remove file test2
ALTER DATABASE test
remove filegroup tesst_group

--显示插入以及identity值的引用
set identity_insert teacher on
insert into teacher(ID,Name,Sex,Phone,Sallary) values(@@IDENTITY+1,‘wangying‘,‘nv‘,‘1812‘,10000)   
select * from teacher
set identity_insert teacher off    

set identity_insert teacher on                                                             
insert into teacher(ID,Name,Sex,Phone,Sallary) values(1,‘wangying‘,‘nv‘,‘1812‘,10000)
select * from teacher
set identity_insert teacher off

--在insert into该table时，不能指定该identity栏位的值
insert into teacher(Name,Sex,Phone,Sallary) values(‘wangying‘,‘nv‘,‘1812‘,10000)   
select * from teacher

insert into teacher values(‘wangying‘,‘nv‘,‘1812‘,10000,null,null,null)  
select * from teacher

--查询目前identity的最大值
dbcc checkident(‘teacher‘,NORESEED)

--修改目前identity的最大值以及重设该值
dbcc checkident(‘teacher‘,RESEED,100)
dbcc checkident(‘teacher‘,RESEED)