SQL的基本操作

记录SQL的基本操作

创建表:

字段的默认值约束
字段是否可为空约束
字段唯一性约束
表的主键约束
表的外键约束
列中的值的范围约束

字段的类型
表的索引

CREATE TABLE Department
(
Id int identity(1,2) primary key,
Fid int not null,
Code varchar(20),
name nvarchar(20),
statusCode char(1) ,
CHECKCODE INT,
DelFlag bit default(0) not null,
CreateDate datetime,
--check(statusCode!='A')--添加check约束
CONSTRAINT chk_Person CHECK (CHECKCODE>1 AND Code='Sandnes'),
CONSTRAINT chk_Person1 CHECK (name='C' or name='B'),
-- Foreign key (Fid) references Department1(Id)--不加外键名称，自动生成
--constraint F_k foreign key (Fid) references Department1(Id)--自定义外键名称
)

CREATE TABLE Department1
(
Id int identity(1,2) primary key,

Code varchar(20),
name nvarchar(20),
statusCode char(1),
DelFlag bit not null,
CHECKCODE INT,
CreateDate datetime

)

--添加删除约束--


--unique 
alter table Department1
add constraint U_k unique (id)

alter table Department1
drop constraint U_k


--Primarykey
alter table Department1
add constraint P_K primary key (id)

alter table Department1
drop constraint P_K

--Foreign Key
alter table Department1
add constraint F_kss foreign key (Id) references Department(Id)

alter table Department1
drop constraint F_kss

--CHECK
alter table Department1
add constraint C_K CHECK(CHECKCODE>5)

alter table Department1
drop constraint C_K

-- 可空约束/其实就是修改列属性
alter table Department1
alter column Code varchar(20) not null

--默认约束
alter table Department1
add constraint d_k default(0) for DelFlag

---------------------------------------------

--修改和增加列
alter table Department1
alter column Code varchar(20) not null

alter table Department1
add Code1 varchar(20) not null

--创建/删除索引

CREATE INDEX INDEX_A 
ON Department1 (CODE,NAME)

DROP INDEX Department1.INDEX_A

--重命名列名

EXEC sp_rename '表名.旧列名', '新列名', 'column'
--例：
EXEC sp_rename 'CustomerProduct.CustomerProductName', 'CustomerProductCode', 'column'