Question

如何配置三个表之间的关系以获取所有相关数据？

我有以下模型（以及数据库中的相同表格）：

public class Client 
{
  public Guid ClientId { get; set; }
  public string FirstName { get; set; }

  public virtual ClientCard ClientCard { get; set; }
}

public class Card
{
  public Guid CardId { get; set; }
  public string Number { get; set; }

  public virtual ClientCard ClientCard { get; set; }
}

public class ClientCard
{
  public Guid ClientCardId { get; set; }
  public Guid CardId { get; set; }
  public Guid ClientId { get; set; }

  public virtual Client Client { get; set; }
  public virtual Card Card { get; set; }
}

以下的OnModelCreating方法：

protected override void OnModelCreating(DbModelBuilder builder)
    {
        builder.Conventions.Remove<PluralizingTableNameConvention>();

        ...

        builder.Entity<ClientCard>()
            .HasKey(x => x.ClientCardId);

        builder.Entity<ClientCard>()
            .HasRequired(x => x.Client)
            .WithRequiredPrincipal(x => x.ClientCard);

        builder.Entity<ClientCard>()
            .HasRequired(x => x.Card)
            .WithRequiredPrincipal(x => x.ClientCard);

        base.OnModelCreating(builder);
    }

但结果在没有相关数据的情况下返回。为什么呢？

Answer 1

对于您的代码，请尝试以下内容：

    builder.Entity<Client>()
           .HasKey(t => t.ClinetID);
    ....
    builder.Entity<Client>()
           .HasMany(a => a.ClientCard)
           .WithRequired(p => p.Client)
           .HasForeignKey(p => p.ClientID);

并映射：

    ....
    builder.Entity<Card>()
           .HasMany(a => a.ClientCard)
           .WithRequired(p => p.Card)
           .HasForeignKey(p => p.CardID);

卡片

error-channel

但我认为最好的方法是为每个实体创建一个单独的地图文件

Answer 2

现在我使用以下型号：

public class Client 
{
   public Guid ClientId { get; set; }
   public string FirstName { get; set; }

   public Guid? CardId { get; set; }
   public virtual Card Card { get; set; }
}

public class Card
{
   public Guid CardId { get; set; }
   public string Number { get; set; }

   //public virtual Client Client { get; set; }
}

以及以下OnModelCreating方法：

protected override void OnModelCreating(DbModelBuilder builder)
{
        builder.Conventions.Remove<PluralizingTableNameConvention>();

        ... 

        builder.Entity<Client>()
            .HasOptional(x => x.Card)
            //.WithOptionalPrincipal(x=> x.Client) 
            //or
            //.WithOptionalDependent(x=> x.Client)
            ;

        base.OnModelCreating(builder);
}

所有客户返回相关数据（如果存在）。但是如果我想要使用Card对象获取相关数据并取消注释public virtual Client Client { get; set; }和WithOptionalPrincipal / WithOptionalDependent，我总是会遇到这些SqlException：＆＃34;无效的列名称＆＃39; Client_ClientId＆＃39;＆＃34; （如果使用WithOptionalPrincipal）或＆＃34;无效的列名＆＃39; Card_CardId＆＃39;＆＃34; （如果使用WithOptionalDependent）

Answer 3

我终于为我的案子找到了一个解决方案。

首先，我从Client类中删除了CardId。其次，我改变了我的OnModelCreating方法：

protected override void OnModelCreating(DbModelBuilder builder)
    {
        builder.Conventions.Remove<PluralizingTableNameConvention>();

        ...

        builder.Entity<Client>()
            .HasOptional(x => x.Card)
            .WithOptionalDependent(x => x.Client)
            .Map(x => x.MapKey("CardId"))
            .WillCascadeOnDelete(false);

        builder.Entity<Card>()
            .HasOptional(x => x.Client)
            .WithOptionalPrincipal(x => x.Card)
            .WillCascadeOnDelete(false);

        base.OnModelCreating(builder);
    }

实体框架Fluent API映射问题

3 个答案: