GO

--判断表是否存在方式1

if object_id(N'EF_User',N'U') is null

--判断表是否存在方式2

--if not exists (select * from dbo.SysObjects WHERE id = object_id(N'[EF_User]') AND OBJECTPROPERTY(ID, 'IsTable') = 1)

begin

--直接创建自增且指定主键约束的表

CREATE TABLE [dbo].[EF_User](

    [ID] [int] identity(1,1) not null,

    [loginName] [nvarchar](100) NULL,

    [realName] [nvarchar](100) NULL,

    [phoneNo] [nvarchar](100) NULL,

    CONSTRAINT [PK_User] PRIMARY KEY(ID)

)

--删除主键约束

alter table [dbo].[EF_User] drop constraint PK_User

--添加主键约束

alter table [dbo].[EF_User] add constraint PK_User primary key(ID)

end

GO

CREATE TABLE [dbo].[EF_Role](

    [ID] [int] identity(1,1) not null,

    [Name] [nvarchar](100) NULL,

    [remark] [nvarchar](100) NULL,

    constraint [PK_Role] Primary Key(ID)

) 

GO

CREATE TABLE [dbo].[EF_User_Role](

    [UserID] [int] NOT NULL,

    [RoleID] [int] NOT NULL

)

--添加外键约束

alter table EF_User_Role add constraint FK_User_Role_User foreign key (UserID)

references EF_User(ID)

alter table EF_User_Role add constraint FK_User_Role_Role foreign key (RoleID)

references EF_Role(ID)

GO