Question

我一直在拉我的头发试图找出我认为相对简单的关系映射（一对多）。

让我们回顾一下模特中的内容：

ContentExternalLink

public class ContentExternalLink
{
    public ContentExternalLink()
    {
        ContentTagAssignments = new List<ContentTagAssignment>();
    }

    [Key]
    public string LinkId { get; set; }
    public string LinkTypeId { get; set; }
    public string LinkTitle { get; set; }
    public string LinkUrl { get; set; }
    public string LinkSource { get; set; }
    public string LinkPhoneNumber { get; set; }
    public DateTime LinkDate { get; set; }
    public DateTime LinkCreatedDate { get; set; }
    public DateTime LinkModifiedDate { get; set; }
    [ScriptIgnore]
    public virtual ICollection<ContentTagAssignment> ContentTagAssignments { get; set; }
}

ContentTagAssignmnent

public class ContentTagAssignment
{
    public ContentTagAssignment()
    {
        this.ContentExternalLink = new ContentExternalLink();
    }

    [Key]
    public string TagId { get; set; }
    [Key]
    public string ArticleId { get; set; }
    public bool IsPrimary { get; set; }
    public DateTime CreatedDate { get; set; }
    [ScriptIgnore]
    public virtual ContentExternalLink ContentExternalLink { get; set; }
}

现在进入映射：

ContentExternalLinkMap

public class ContentExternalLinkMap : EntityTypeConfiguration<ContentExternalLink>
{
    public ContentExternalLinkMap()
    {
        this.ToTable("content_external_link", "dbo");

        this.HasKey(c => c.LinkId);

        this.Property(c => c.LinkId).HasColumnName("link_id");
        this.Property(c => c.LinkTypeId).HasColumnName("link_type_id");
        this.Property(c => c.LinkTitle).HasColumnName("link_title");
        this.Property(c => c.LinkUrl).HasColumnName("link_url");
        this.Property(c => c.LinkSource).HasColumnName("link_source");
        this.Property(c => c.LinkPhoneNumber).HasColumnName("link_phone_number");
        this.Property(c => c.LinkDate).HasColumnName("link_date");
        this.Property(c => c.LinkCreatedDate).HasColumnName("link_created_date");
        this.Property(c => c.LinkModifiedDate).HasColumnName("link_modified_date");
    }
}

ContentTagAssignmnetMap

public class ContentTagAssignmentMap : EntityTypeConfiguration<ContentTagAssignment>
{
    public ContentTagAssignmentMap()
    {
        this.ToTable("content_tag_assignment", "dbo");

        this.HasKey(t => new {t.TagId, t.ArticleId});

        this.Property(t => t.TagId).HasColumnName("tag_id");
        this.Property(t => t.ArticleId).HasColumnName("article_id");
        this.Property(t => t.IsPrimary).HasColumnName("is_primary_tag");
        this.Property(t => t.CreatedDate).HasColumnName("created_date");


        this.HasOptional(t => t.ContentExternalLink)
            .WithMany(t => t.ContentTagAssignments)
            .HasForeignKey(t => new {t.TagId, t.ArticleId});
    }
}

这种关系肯定是奇怪的，因为LinkId会与ContentTagAssignment中的ArticleId匹配。

我在ContentTagAssignmentMap中尝试了以下内容：

    //this.HasOptional(t => t.ContentExternalLink)
//    .WithMany(t => t.ContentTagAssignments)
//    .HasForeignKey(t => t.ContentExternalLink);

this.HasOptional(x => x.ContentExternalLink)
    .WithMany(x=>x.ContentTagAssignments)
    .Map(x => x.MapKey("LinkId").HasColumnAnnotation("LinkId","ArticleId",null));

//this.Map(m =>
//    {
//        m.Properties(x => x.ArticleId);
//        m.ToTable("content_tag_assignment");
//    })
//    .Map(p =>
//    {
//        p.Properties(x => x.ContentExternalLink.LinkId);
//        p.ToTable("ContentExternalLink");
//    });

评论的关系不起作用。有效的（因为它在初始页面加载时不会失败）。但是，当我尝试从ContentExternalLink访问列表时，出现以下错误：{＆＃34;列名称无效＆＃39; LinkId＆＃39;。\ r \ n无效的列名称＆＃39; LinkId＆＃39; ＆＃34;}

所以我更失落......

问题

基本上，并非每个ContentExternalLink都会为其分配标记。但是，如果有ContentTternalAternal的ContentTagAssignments，我应该能够得到它们的列表。此外，TagId和ArticleId是字符串（guids）。

有人有任何建议吗？

谢谢！

Answer 1

在ivan stoev的评论之后，我发现当外键也是主键（not nullable）

时，这里的唯一错误是设置可选

所以映射将是：

public class ContentTagAssignmentMap : EntityTypeConfiguration<ContentTagAssignment>
{
    public ContentTagAssignmentMap()
    {
        this.ToTable("content_tag_assignment", "dbo");

        this.HasKey(t => new { t.TagId, t.ArticleId });

        this.Property(t => t.TagId).HasColumnName("tag_id");
        this.Property(t => t.ArticleId).HasColumnName("article_id");
        this.Property(t => t.IsPrimary).HasColumnName("is_primary_tag");
        this.Property(t => t.CreatedDate).HasColumnName("created_date");


        this.HasRequired(t => t.ContentExternalLink)
            .WithMany(t => t.ContentTagAssignments)
            .HasForeignKey(t => t.ArticleId)
            .WillCascadeOnDelete(false);
    }
}

以下是您的模型的工作示例：

class Program
{
    static void Main(string[] args)
    {
        var ctx = new Context();
        ctx.Database.Delete();
        ctx.Database.CreateIfNotExists();

        Console.ReadKey();
    }
}

public class Context : DbContext
{
    public Context():base ("Teste")
    {

    }

    public DbSet<ContentExternalLink> ContentExternalLinks { get; set; }
    public DbSet<ContentTagAssignment> ContentTagAssignments { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Configurations.Add(new ContentExternalLinkMap());
        modelBuilder.Configurations.Add(new ContentTagAssignmentMap());

        base.OnModelCreating(modelBuilder);
    }

}

public class ContentExternalLink
{
    public ContentExternalLink()
    {
        ContentTagAssignments = new List<ContentTagAssignment>();
    }

    [Key]
    public string LinkId { get; set; }
    public string LinkTypeId { get; set; }
    public string LinkTitle { get; set; }
    public string LinkUrl { get; set; }
    public string LinkSource { get; set; }
    public string LinkPhoneNumber { get; set; }
    public DateTime LinkDate { get; set; }
    public DateTime LinkCreatedDate { get; set; }
    public DateTime LinkModifiedDate { get; set; }

    public virtual ICollection<ContentTagAssignment> ContentTagAssignments { get; set; }
}

public class ContentTagAssignment
{
    public ContentTagAssignment()
    {
        this.ContentExternalLink = new ContentExternalLink();
    }

    [Key]
    public string TagId { get; set; }
    [Key]
    public string ArticleId { get; set; }
    public bool IsPrimary { get; set; }
    public DateTime CreatedDate { get; set; }

    public virtual ContentExternalLink ContentExternalLink { get; set; }
}

public class ContentExternalLinkMap : EntityTypeConfiguration<ContentExternalLink>
{
    public ContentExternalLinkMap()
    {
        this.ToTable("content_external_link", "dbo");

        this.HasKey(c => c.LinkId);

        this.Property(c => c.LinkId).HasColumnName("link_id");
        this.Property(c => c.LinkTypeId).HasColumnName("link_type_id");
        this.Property(c => c.LinkTitle).HasColumnName("link_title");
        this.Property(c => c.LinkUrl).HasColumnName("link_url");
        this.Property(c => c.LinkSource).HasColumnName("link_source");
        this.Property(c => c.LinkPhoneNumber).HasColumnName("link_phone_number");
        this.Property(c => c.LinkDate).HasColumnName("link_date");
        this.Property(c => c.LinkCreatedDate).HasColumnName("link_created_date");
        this.Property(c => c.LinkModifiedDate).HasColumnName("link_modified_date");
    }
}

public class ContentTagAssignmentMap : EntityTypeConfiguration<ContentTagAssignment>
{
    public ContentTagAssignmentMap()
    {
        this.ToTable("content_tag_assignment", "dbo");

        this.HasKey(t => new { t.TagId, t.ArticleId });

        this.Property(t => t.TagId).HasColumnName("tag_id");
        this.Property(t => t.ArticleId).HasColumnName("article_id");
        this.Property(t => t.IsPrimary).HasColumnName("is_primary_tag");
        this.Property(t => t.CreatedDate).HasColumnName("created_date");


        this.HasRequired(t => t.ContentExternalLink)
            .WithMany(t => t.ContentTagAssignments)
            .HasForeignKey(t => t.ArticleId)
            .WillCascadeOnDelete(false);
    }
}

以下是上述代码的结果：

Answer 2

您的实体模型/实施存在两个问题。

让我们从simlpler开始（在Gert Arnold's comment中提到）。根据经验，您不应该在构造函数（或内部任何其他位置）内初始化单个导航属性，因为这会破坏EF延迟加载行为。

很快，只需删除

this.ContentExternalLink = new ContentExternalLink();

来自ContentTagAssignment类构造函数的行。

现在主要问题。 EF6仅支持引用主端的PK（主键）的FK（外键）关系。这意味着您无法在TagId, ArticleId实体中使用复合键（ContentTagAssignment）来引用LinkId实体的单个PK（ContentExternalLink），因为您尝试设置通过HasForeignKey(t => new {t.TagId, t.ArticleId})电话。这两列构成从属端（ContentTagAssignment）的PK的事实与关系无关。没有其他选择 - 您必须从两个字段中选择一个。根据 LinkId将与ContentTagAssignment 中的ArticleId匹配，这应该是ArticleId字段。

如果我的猜测是正确的，只需替换

this.HasOptional(t => t.ContentExternalLink)
    .WithMany(t => t.ContentTagAssignments)
    .HasForeignKey(t => new {t.TagId, t.ArticleId});

与

this.HasRequired(t => t.ContentExternalLink)
    .WithMany(t => t.ContentTagAssignments)
    .HasForeignKey(t => t.ArticleId);

并且（连同构造函数修改）应该解决问题。

请注意，我还将HasOptional更改为HasRequired，因为ArticleId字段是PK的一部分，因此无论如何都不会允许null值。

Answer 3

我认为问题在于您尝试使用外键而未指示正确的连接。

您需要做的是将一个LinkId字段添加到ContentTagAssignment，这是您应该使用的实际外键并加入到该字段：

this.HasOptional(t => t.ContentExternalLink)
.WithMany(t => t.ContentTagAssignments)
.HasForeignKey(t => t.LinkId);

原因是你要告诉它找一个ContentExternalLink中不存在的密钥（tagId，ArticleId）。

EF 6关系：在模型生成期间检测到一个或多个验证错误

3 个答案: