Entity Framework Code First 一對一關聯設定

Nov 24, 2014

1 min read

在兩個類別之間，各自包含一個引用屬性，就會被當成一對一關系只是那張是主資料表，需要利用Fluent API來設定

主資料表

using System.ComponentModel.DataAnnotations;
public partial class TableA
{
[Key]
public int TabId { get; set; }
public int C1 { get; set; }

public virtual TableB TableB { get; set; }

}

對應的資料表

using System.ComponentModel.DataAnnotations;
public partial class TableB
{
[Key]
public int TabId { get; set; }
public int CC1 { get; set; }

public virtual TableA TableA { get; set; }

}

設定關聯

using System.Data.Entity;
public partial class DemoContext : DbContext
{
public DemoContext()
: base(“name=DemoContext”)
{
}
public virtual DbSet&lt;TableA&gt; TableA { get; set; }
public virtual DbSet&lt;TableB&gt; TableB { get; set; }

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity&lt;TableA&gt;()
        .HasOptional(x =&gt; x.TableB)
        .WithRequired(x =&gt; x.TableA);
}

}

建立出一對一關系的資料表

[![](http://2.bp.blogspot.com/-rbt4EUaTb5Q/VHL9dejT89I/AAAAAAAABwI/QiNQmRhMIfo/s1600/%E6%9C%AA%E5%91%BD%E5%90%8D.png)](http://2.bp.blogspot.com/-rbt4EUaTb5Q/VHL9dejT89I/AAAAAAAABwI/QiNQmRhMIfo/s1600/%E6%9C%AA%E5%91%BD%E5%90%8D.png)

關聯圖

[![](http://3.bp.blogspot.com/-4NfXgZRL470/VHL_AJYWIvI/AAAAAAAABwU/0OA1cJHzG5s/s1600/%E6%9C%AA%E5%91%BD%E5%90%8D.png)](http://3.bp.blogspot.com/-4NfXgZRL470/VHL_AJYWIvI/AAAAAAAABwU/0OA1cJHzG5s/s1600/%E6%9C%AA%E5%91%BD%E5%90%8D.png)