1.新建一數據表,裏面有字段id,將id設爲爲主鍵ide
複製代碼 代碼以下:.net
create table tb(id int,constraint pkid primary key (id))
create table tb(id int primary key )get
2.新建一數據表,裏面有字段id,將id設爲主鍵且自動編號it
複製代碼 代碼以下:table
create table tb(id int identity(1,1),constraint pkid primary key (id))
create table tb(id int identity(1,1) primary key )class
3.已經建好一數據表,裏面有字段id,將id設爲主鍵object
複製代碼 代碼以下:im
alter table tb alter column id int not null
alter table tb add constraint pkid primary key (id)數據
4.刪除主鍵tab
複製代碼 代碼以下:
Declare @Pk varChar(100);
Select @Pk=Name from sysobjects where Parent_Obj=OBJECT_ID('tb') and xtype='PK';
if @Pk is not null exec('Alter table tb Drop '+ @Pk)