创建任意数据库，执行以下测试sql脚本

USE TestDB

GO

--PK, 主键, {PK_Table}

CREATE TABLE [Users](

[Id] [int] IDENTITY (1,1)

CONSTRAINT [PK_Users] PRIMARY KEY([Id]),

[Name] [nvarchar](255)

);

GO

--INSERT INTO [Users]([Name])VALUES('demo user');

--SELECT * FROM [Users];

--UK, 唯一约束, {UK_Table_Column}

CREATE TABLE [Users2](

[Id] [int] IDENTITY (1,1)

CONSTRAINT [PK_Users2]

PRIMARY KEY([Id]),

[Name] [nvarchar](255)

CONSTRAINT [UK_Users2_Name]

UNIQUE ([Name]),

);

--INSERT INTO [Users2]([Name])VALUES('demo user');

----再次创建违反唯一约束

--INSERT INTO [Users2]([Name])VALUES('demo user');

--SELECT * FROM [Users2];

--DF, 默认约束, {DF_Table_Column}

CREATE TABLE [Users3](

[Id] [int] IDENTITY (1,1)

CONSTRAINT [PK_Users