Question

我有以下课程，一切都很好。但是在我在AB表中找到的数据库中生成的表中：

Id, AId, BId

它应该是怎么样的，另外两列不应该是AId1＆amp; AId2他们也是外键。

A类

public class A
{
    public int Id { get; set; }
    ICollection<AB> ABs { get; set; }
}

B类

public class B
{
    public int Id { get; set; }
    ICollection<AB> ABs { get; set; }
}

AB类

public class AB
{
    public int Id { get; set; }
    public A A { get; set; }
    public B B { get; set; }
    public int AId { get; set; }
    public int BId { get; set; }
}

ABMapping

public class ABMap : EntityTypeConfiguration<AB>
{
        public ABMap()
        {
            this.HasKey(a => a.Id);

            this.HasRequired(e => e.A)
                .WithMany()
                .HasForeignKey(e => e.AId)
                .WillCascadeOnDelete(false);

            this.HasRequired(c => c.B)
                .WithMany()
                .HasForeignKey(e => e.BId)
                .WillCascadeOnDelete(false);

            this.Property(e => e.AId)
                    .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_AB", 1) { IsUnique = true }));
            this.Property(e => e.BId)
                    .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_AB", 2) { IsUnique = true }));
        }
    }

上下文

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
        //...
        modelBuilder.Configurations.Add(new ABMap());
        //...
}

Answer 1

您需要在致电WithMany时指定集合属性。因为您没有告诉EF两个ABs集合是您定义的关系的一部分，所以创建了两个额外的一对多关系。将您的流畅API映射更改为以下内容。

public class ABMap : EntityTypeConfiguration<AB>
{
    public ABMap()
    {
        this.HasKey(a => a.Id);

        this.HasRequired(e => e.A)
            .WithMany(a => a.ABs)
            .HasForeignKey(e => e.AId)
            .WillCascadeOnDelete(false);
        this.Property(a => a.AId);

        this.HasRequired(c => c.B)
            .WithMany(b => b.ABs)
            .HasForeignKey(e => e.BId)
            .WillCascadeOnDelete(false);
        this.Property(a => a.BId);

        this.Property(e => e.AId)
                .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_AB", 1) { IsUnique = true }));
        this.Property(e => e.BId)
                .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_AB", 2) { IsUnique = true }));
    }
}

实体框架在数据库中生成额外的外键

1 个答案: