Question

我有两节课。

public class Om_MembershipCharges
{
    [Key]
    public Int32 MembershipChargesID { get; set; }
    public Decimal Amount { get; set; }
    public Int16 PerMonth { get; set; }
    public Int16? MemebershipTypeID { get; set; }

    public virtual Om_MembershipType MemebershipType { get; set; }
}

public class Om_MembershipType
{
    [Key]
    public Int16 MemebershipTypeID { get; set; }
    public String MemebershipType { get; set; }
    public Boolean IsDefaultMembership { get; set; }

    public virtual ICollection<Om_MembershipCharges> MembershipCharges { get; set; }
}

数据库模型如下。

public MembershipTypeMap()
{
    Property(x => x.MemebershipTypeID)
.HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
    Property(x => x.MemebershipType)
        .IsRequired()
        .HasMaxLength(100)
        .HasColumnAnnotation
        (
            IndexAnnotation.AnnotationName,
            new IndexAnnotation
            (
                new IndexAttribute("U_MembershipType", 1) { IsUnique = true }
            )
        );

    Property(x => x.IsDefaultMembership).IsRequired();
    ToTable(clsCommon.tblMembershipType);
}


public class MembershipChargesMap : EntityTypeConfiguration<Om_MembershipCharges>
{
    public MembershipChargesMap()
    {
        Property(x => x.MembershipChargesID);

        Property(x => x.Amount).IsRequired();
        Property(x => x.PerMonth).IsRequired();
        Property(x => x.MemebershipTypeID).IsOptional();    
        ToTable(clsCommon.tblMembershipCharges);
    }
}

以下是约束

modelBuilder.Entity<Om_MembershipCharges>()
       .HasOptional(x => x.MemebershipType)
       .WithMany().HasForeignKey(x => x.MemebershipTypeID)
       .WillCascadeOnDelete(false);


modelBuilder.Entity<Om_MembershipCharges>()
    .HasRequired(m => m.MemebershipType).WithMany(m => m.MembershipCharges)
    .HasForeignKey(m => m.MembershipChargesID).WillCascadeOnDelete(false);

我面临下面的异常以前有人遇到过这类问题吗？

在模型生成期间检测到一个或多个验证错误：

Om_MembershipCharges_MemebershipType_Source ::多重性不是   在角色和Om_MembershipCharges_MemebershipType_Source＆＃39;中有效在   关系＆＃39; Om_MembershipCharges_MemebershipType＆＃39;。因为   依赖角色是指关键属性，即上界   依赖角色的多样性必须是＆＃39; 1＆＃39;。   Om_MembershipCharges_MemebershipType_Target_Om_MembershipCharges_MemebershipType_Source：   ：参照的从属角色中的所有属性的类型   约束必须与相应的属性类型相同   主要角色。财产的类型＆＃39; MembershipChargesID＆＃39;在实体上   ＆＃39; Om_MembershipCharges＆＃39;与财产类型不匹配   ＆＃39; MemebershipTypeID＆＃39;实体＆＃39; Om_MembershipType＆＃39;在参考   约束＆＃39; Om_MembershipCharges_MemebershipType＆＃39;。

Answer 1

您的上一个代码段...

modelBuilder.Entity<Om_MembershipCharges>()
    .HasRequired(m => m.MemebershipType).WithMany(m => m.MembershipCharges)
    .HasForeignKey(m => m.MembershipChargesID).WillCascadeOnDelete(false);

...覆盖m.MembershipType的先前注册，现在使其成为必需，EF表示其多样性应为1，而不是0..1。

看到导航属性，映射应该是最后两个片段的合并（请注意HasOptional）。和您应该使用MembershipTypeID代替MembershipChargesID：

modelBuilder.Entity<Om_MembershipCharges>()
    .HasOptional(m => m.MemebershipType).WithMany(m => m.MembershipCharges)
    .HasForeignKey(m => m.MembershipTypeID).WillCascadeOnDelete(false);

旁注：我会将所有映射代码放入映射类中。维护更容易将它们保持在一起。我认为您甚至还需要这样做，因为除了EntityTypeConfiguration注册类型外，EF不会允许您注册modelBuilder.Entity<T>。

使用Fluent API EF Code First约束问题

1 个答案: