问题是在 Admin $ c $中的两个名称 c>和 Staff 当然不能同时映射到中的名称属性。

但是您可以有两个不同的名称属性，并将两者映射到两个表中的相同列名称：

用户中的更改：

  public用户
 {
 [Key] 
 public string Username {get;组; } 
 ... 
 public string AdminName {get;组; } 
 public string StaffName {get;组; } 
 ... 
} 
 

映射片段：

  .Map（map => 
 {
 map.Properties（p => new 
 {
 p.Username，
 p.AdminName 
}）; 
 map.Property（p => p.AdminName）.HasColumnName（Name）; 
 map.ToTable（Admin）; 
}）。Map（map => 
 {
 map.Properties（p => new 
 {
 p.Username，
 p.StaffName，
 p.Phone，
 p.Position 
}）; 
 map.Property（p => p.StaffName） .HasColumnName（Name）; 
 map.ToTable（Staff）; 
}）; 
 

I'm facing a problem using EF. I have the following situation:

Table User: Username, Password, RoleId, IsActive, CreatedDate, ActivedDate

Table Admin: Username, Name

Table Staff: Username, Name, Position, Phone

From this database schema i'd like to generate the following entity by merge tables data:

public class User
{
    [Key]
    public string Username { get; set; }
    public string Password { get; set; }
    public int RoleId { get; set; }
    public bool IsActive { get; set; }
    public DateTime CreatedDate { get; set; }
    public DateTime ActivedDate { get; set; }

    public string Name { get; set; }
    public string Phone { get; set; }
    public string Position { get; set; }

    [ForeignKey("RoleId")]
    public Role Role { get; set; }
}

configuration class:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
            .Map(map =>
            {
                map.Properties(p => new
                {
                    p.Username,
                    p.Password,
                    p.RoleId,
                    p.IsActive,
                    p.CreatedDate,
                    p.ActivedDate
                });
                map.ToTable("User");
            })
            .Map(map =>
            {
                map.Properties(p => new
                {
                    p.Username,
                    p.Name
                });
                map.ToTable("Admin");
            }).Map(map =>
            {
                map.Properties(p => new
                {
                    p.Username,
                    p.Name,
                    p.Phone,
                    p.Position
                });
                map.ToTable("Staff");
            });

        base.OnModelCreating(modelBuilder);
    }

I've tested it but it doesn't work as expected. I always get this message:

Properties for type 'User' can only be mapped once. The non-key property 'Name' is mapped more than once. Ensure the Properties method specifies each non-key property only once.

Am I missing something?

The problem is that the two Names in Admin and Staff of course can't both be mapped onto one Name property in User.

But you can have two different name properties and map both to the same column names in two tables:

Changes in User:

public class User
{
    [Key]
    public string Username { get; set; }
    ...
    public string AdminName { get; set; }
    public string StaffName { get; set; }
    ...
}

And the mapping fragments:

.Map(map =>
{
    map.Properties(p => new
    {
        p.Username,
        p.AdminName
    });
    map.Property(p => p.AdminName).HasColumnName("Name");
    map.ToTable("Admin");
}).Map(map =>
{
    map.Properties(p => new
    {
        p.Username,
        p.StaffName,
        p.Phone,
        p.Position
    });
    map.Property(p => p.StaffName).HasColumnName("Name");
    map.ToTable("Staff");
});