使用数据注释的多对多映射 [英] Many to Many Mapping Using Data Annotations

问题描述

[Table("UserMaster")]
public class UserMaster  
{
    public UserMaster()
    {
        this.Roles = new List<Role>();
    }

    [Key]    
    public int UserId { get; set; }
    public string UserName { get; set; }
    public ICollection<Role> Roles { get; set; }
 } 



[Table("Role")]
public class Role 
{
    public Role()
    {
        this.Users = new List<UserMaster>();
    }
    public int RoleId{ get; set; }
    public string Name{ get; set; }
    public ICollection<UserMaster> Users { get; set; }

}

我使用EntityTypeConfiguration映射这些表，并触发OnModelCreate

I map these tables using EntityTypeConfiguration and it triggers OnModelCreate

this.HasMany(a => a.Roles).WithMany(b => b.Users).Map(m =>
        {
            m.MapLeftKey("UserId");
            m.MapRightKey("RoleId");
            m.ToTable("UsersInRoles");
        });

我想知道如果有一种方法将其映射到Role或UserMaster类中。我们可以使用

I wonder If there Is a way to map them in the class Role or UserMaster. We can use

[ForeignKey()]
[Key]
[Table()]

我们可以做映射的东西吗？

Could we do the mapping thing also?

推荐答案

如果要使用数据注释来首先定义实体框架代码，以达到多对多关系，则必须添加交换类，如下所示：

If you want to customize entity framework code first for many to many relationship using data annotation, you must add junction class as the following :

[Table("UsersInRoles")]
public class UsersInRoles
{
    [Key]
    [Column(Order = 1)]
    [ForeignKey("UserMaster")]
    public int UserId { get; set; }

    [Key]
    [Column(Order = 2)]
    [ForeignKey("Role")]
    public int RoleId { get; set; }

    public UserMaster UserMaster { get; set; }
    public Role Role { get; set; }
}

然后相关类必须更改为：

and then related classes must be changed to :

[Table("UserMaster")]
public class UserMaster  
{
    public UserMaster()
    {
        this.Roles = new List<Role>();
    }

    [Key]    
    public int UserId { get; set; }
    public string UserName { get; set; }

    public ICollection<UsersInRoles> UsersInRoles { get; set; }
 } 



[Table("Role")]
public class Role 
{
    public Role()
    {
        this.Users = new List<UserMaster>();
    }
    public int RoleId{ get; set; }
    public string Name{ get; set; }

    public ICollection<UsersInRoles> UsersInRoles { get; set; }
}

，还可以看到这个。

这篇关于使用数据注释的多对多映射的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！