DB First先有数据库，根据数据库生成Model实体对象。

1、新建数据库表,Poet,Poem,Meter.关系如下：

　　

 

　　建表语句

create table Poet(    PoetId int identity(1,1) primary key,    FirstName varchar(20),    MiddleName varchar(20),    LastName varchar(20))create table Meter(    MeterId int identity(1,1) primary key,    MeterName varchar(50) )create table Poem(    poemId int identity(1,1) primary key,    PoetId int,    MeterId int,    Title varchar(50),    foreign key(PoetId) references poet(Poetid),    foreign key(MeterId) references Meter(MeterId))create view vwLibraryasselect  poet.FirstName,poet.MiddleName,poet.LastName,poem.Title,Meter.MeterName from Meter ,poet,Poem where Meter.MeterId=poem.MeterId and poem.PoetId=poet.PoetId

2、新建控制台项目DBFirstDemo,确定。

3、点击选中项目添加-->新建-->选择数据模板-->ADO.NET实体数据模型，确定。

　　

4、实体模型向导选择从数据库生成，下一步。

　　

5、选择或者新建链接，连接选择后继续下一步。

　　

6、选择框架版本，本机选择6.0

　　

7、选择数据库对象，选择表和视图。并勾选下方复选框。

　　

8、生成实体图上展示如下：

　　

9、使用实体，修改Main方法如下：

　　

static void Main(string[] args)        {            using (var context = new EF6RecipesEntities())            {                var poet = new poet { FirstName = "John", LastName = "Milton" };                var poem = new Poem { Title = "Paradis Lost" };                var meter = new Meter { MeterName = "Iambic Pentameter" };                poem.poet = poet;                poem.Meter = meter;                context.Poems.Add(poem);                poem = new Poem { Title="Paradis Regained" };                poem.poet = poet;                poem.Meter = meter;                context.Poems.Add(poem);                poet = new poet { FirstName = "Lewis", LastName = "Carroll" };                poem = new Poem { Title = "The Hunting of the Shark" };                meter = new Meter { MeterName = "Anapestic Tetrameter" };                poem.Meter = meter;                poem.poet = poet;                context.Poems.Add(poem);                poet = new poet { FirstName = "Lord", LastName = "Byron" };                poem = new Poem { Title = "Don Juan" };                poem.Meter = meter;                poem.poet = poet;                context.Poems.Add(poem);                context.SaveChanges();                Console.WriteLine("----------------读取Poet----------------");                var poets = context.poets;                foreach (var poettemp in poets)                {                    Console.WriteLine("{
     0}{
    1}", poettemp.FirstName, poettemp.LastName);                    foreach (var poemtemp in poet.Poems)                    {                        Console.WriteLine("\t{
     0} ({
    1})", poemtemp.Title, poemtemp.Meter.MeterName);                    }                }                Console.ReadKey();            }        }

10、执行结果

　　

 

总结:DBFirst是根据现有数据库生成Model实体，并对实体进行后续操作，适用旧项目改造。