SQLMetal多个外键指向一个表问题

因此,我的解决方案是只添加另一个分部类,并添加一个get/set指向奇怪命名的fkbtablenamegoesher属性的属性。这样我们就不必一直修改生成的类。不能完全解决问题,但应该让开发商更清楚房产意味着什么。有人看到这个解决方案有什么潜在的问题吗?

-所以,显然这只适用于选择数据,而不是基于数据进行过滤。不像我希望的那么容易修复。有人有其他建议吗?

-天哪,我以为这是个常见的问题,但我想不是。不管怎样,事实证明我的想法是对的。我发现这个帖子:

Multiple foreign keys to the same table

这让我想到,我不能直接链接到另一个属性的getter/setter,因为在幕后可能还有很多事情要做。这家伙的解决方案不完全是答案,但它送我向正确的方向。添加关联属性是它的最终目的:

public partial class ProblemClass
{
    [Association(Name = "FK__SomeLinkHere", Storage = "_OriginalPoorlyNamedStorageVariable", ThisKey = "FK_1_Id", OtherKey = "Id", IsForeignKey = true)]
    public FKType MyNewBetterName
    {
        get
        {
            return this._OriginalPoorlyNamedStorageVariable.Entity;
        }

        set
        {
            this.OriginalPoorlyNamedStorageVariable = value;
        }
    }
}

好的,我会提出一个新的答案(有点晚了,对不起),即使协会的名称发生了变化,这个答案仍然有效。

表格: Orders Customers 通过 Orders.CustomerID 等于 Customers.Id CustomerID (这是引用的字段)和 Name (这是我们想要的价值)。

/// <summary>
/// Gets the value of "referencedValueFieldName" of an associated table of the "fieldName" in the "mainTable".
/// This is equivalent of doing the next LINQ query:
///   var qryForeignValue = 
///     from mt in modelContext.mainTable
///     join at in modelContext.associatedTable
///       on mt.fieldName equals at.associatedField
///     select new { Value = at.referencedValueField }
/// </summary>
/// <param name="mainTable">Metadata of the table of the fieldName's field</param>
/// <param name="fieldName">Name of the field of the foreign key</param>
/// <param name="referencedValueFieldName">Which field of the foreign table do you the value want</param>
/// <returns>The value of the referenced table</returns>
/// <remarks>This method only works with foreign keys of one field.</remarks>
private Object GetForeignValue(MetaTable mainTable, string fieldName, string referencedValueFieldName) {
  Object resultValue = null;
  foreach (MetaDataMember member in mainTable.RowType.DataMembers) {
    if ((member.IsAssociation) && (member.Association.IsForeignKey)) {
      if (member.Association.ThisKey[0].Name == fieldName) {
        Type associationType = fPointOfSaleData.GetType();
        PropertyInfo associationInfo = associationType.GetProperty(member.Name);
        if (associationInfo == null)
          throw new Exception("Association property not found on member");

        Object associationValue = associationType.InvokeMember(associationInfo.Name, BindingFlags.GetProperty, null, fPointOfSaleData, null);

        if (associationValue != null) {
          Type foreignType = associationValue.GetType();
          PropertyInfo foreignInfo = foreignType.GetProperty(referencedValueFieldName);
          if (foreignInfo == null)
            throw new Exception("Foreign property not found on assiciation member");

          resultValue = foreignType.InvokeMember(foreignInfo.Name, BindingFlags.GetProperty, null, associationValue, null);
        }

        break;
      }
    }
  }
  return resultValue;
}

      AttributeMappingSource mapping = new System.Data.Linq.Mapping.AttributeMappingSource();
      MetaModel model = mapping.GetModel(typeof(WhateverClassesDataContext));
      MetaTable table = model.GetTable(typeof(Order));
      Object value = GetForeignValue(table, "CustomerId" /* In the main table */, "Name" /* In the master table */);

这是一个获取主表某个字段值的方法,可以修改为返回整个对象。

这个问题很久以前就有了,但我只是碰到了这个问题。我使用的是DBML,我通过编辑关系解决了这个问题。如果展开ParentProperty,则可以通过更改name属性来设置属性名称。

以下是来自DBML的XML(成员属性已更改):

  <Association Name="State_StateAction1" Member="DestinationState" ThisKey="DestinationStateId" OtherKey="Id" Type="State" IsForeignKey="true" />

public partial class ProblemClass
{
    partial void OnCreated()
    {
        this._MyNewBetterName = default(EntityRef<FKType>);
    }
    protected EntityRef<FKType> _MyNewBetterName;

    [Association(Name = "FK__SomeLinkHere", Storage = "_MyNewBetterName", ThisKey = "FK_1_Id", OtherKey = "Id", IsForeignKey = true)]
    public EntityRef<FKType> MyNewBetterName
    {
        get
        {
            return this._MyNewBetterName.Entity;
        }

        set
        {
            this.MyNewBetterName = value;
        }
    }
}

OnCreated() 在每个部分中,因为这些部分不能在c#中继承( see this ).