8.2 使用Fluent API進行實體映射【Code-First系列】 - caofangsheng－IT工程師數位筆記本

文章出處

現在，我們來學習怎么使用Fluent API來配置實體。

一。配置默認的數據表Schema

Student實體

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF4
{
   public class Student
    {
       public int StudentID { get; set; }

       public string StudentName { get; set; }

       public int StuaentAge { get; set; }

       public string StudentEmail { get; set; }

       public Standard Standard { get; set; }
    }
}

Standard實體

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF4
{
   public class Standard
    {
       public int StandardID { get; set; }

       public int StandardName { get; set; }

       public ICollection<Student> Students { get; set; }

    }
}

上下文類：

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF4
{
   public class DBContextClass:DbContext
    {
       public DBContextClass() : base("ConnectionStrings") { }
       public DbSet<Student> Students { get; set; }

       public DbSet<Standard> Standards { get; set; }

       protected override void OnModelCreating(DbModelBuilder modelBuilder)
       {
           modelBuilder.HasDefaultSchema("hello");
           base.OnModelCreating(modelBuilder);
       }
    }
}

然后生成的數據表Schema就是我們配置的【hello】了

當然，你也可以分別對每個表，進行設置Schema。

二。把實體映射成表

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF4
{
   public class DBContextClass:DbContext
    {
       public DBContextClass() : base("ConnectionStrings") { }
       public DbSet<Student> Students { get; set; }

       public DbSet<Standard> Standards { get; set; }

       protected override void OnModelCreating(DbModelBuilder modelBuilder)
       {
           //配置數據表的Schema
           //modelBuilder.HasDefaultSchema("hello");

           //將實體映射成表
           modelBuilder.Entity<Student>().ToTable("WahHaHa");
           modelBuilder.Entity<Standard>().ToTable("StandardInfo","xxx");
           base.OnModelCreating(modelBuilder);
       }
    }
}

然后數據庫是這樣的：

打開表一個一個看：

三。將一個實體，拆分成多個表。

下面的代碼是將Student實體拆分成兩個表。

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF4
{
   public class DBContextClass:DbContext
    {
       public DBContextClass() : base("ConnectionStrings") { }
       public DbSet<Student> Students { get; set; }

       public DbSet<Standard> Standards { get; set; }

       protected override void OnModelCreating(DbModelBuilder modelBuilder)
       {
           //配置數據表的Schema
           //modelBuilder.HasDefaultSchema("hello");

           //將實體映射成表
           //modelBuilder.Entity<Student>().ToTable("WahHaHa");
           //modelBuilder.Entity<Standard>().ToTable("StandardInfo","xxx");

           //將一個實體映射成多個表
           modelBuilder.Entity<Student>().Map(
               m =>
               {

                   m.Properties(p => p.StudentID);
                   m.Properties(p => p.StudentName);
                   m.ToTable("StudentInfo");

               }).Map(
               m => 
               {

                   m.Properties(p => p.StudentID);
                   m.Properties(p => p.StuaentAge);
                   m.Properties(p => p.StudentEmail);
                   m.ToTable("StudentDetails");
               });


           modelBuilder.Entity<Standard>().ToTable("StandardInfo");

           base.OnModelCreating(modelBuilder);
       }
    }
}