SQL Server Code sets the primary key and automatically grows

Create a new data table, set Userid as the primary key, and automatically increase createtableT_UserLogin (UserIdintnotnullprimarykeyidentity (), UserNamenvarchar (50) notnull, Passvarchar (50) notnull, set Userid as the primary key and automatically grow altertablet

Create a new data table, set Userid as the primary key, and automatically increase create table T_UserLogin (UserId int not null primary key identity (), UserName nvarchar (50) not null, Pass varchar (50) not null) modify a data table that has been created, set Userid as the primary key, and automatically add alter table t

Create a new data table, set Userid as the primary key, and automatically increase

Create table T_UserLogin (UserId int not null primary key identity (1, 1), UserName nvarchar (50) not null, Pass varchar (50) not null)

Modify a data table that has been created, set Userid as the primary key, and automatically grow

Alter table tb alter column id int not null

Alter table tb add constraint pkid primary key (id)

Delete primary key

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)