Linq與Sql實體的關聯（非整數主鍵）

Question

我一直在使用Linq to Sql，但是在定義實體之間的關聯時遇到了一個問題。

我有2個表，一個是包含客戶交易的表，另一個是包含交易類型的查找表。 例如，交易可以是“ CASH”類型，並且查找表中的值將具有“ CASH”主鍵和“ Cash Payment”描述。

運行測試程序時，如果將事務和查找表中的主鍵更改為整數，則會收到“無法將類型為'System.Int32'的對象轉換為類型為'System.String'”的錯誤如預期般運作。

我大概缺少一些基本知識，但是我不確定是什么。 任何幫助表示贊賞。

這是我用來映射表的代碼：

[Table(Name = "customer")]
public class Customer
{
    [Column(IsPrimaryKey = true, Name = "customer_id")]
    public int CustomerID { get; set; }

    private EntitySet<Transaction> _Transactions;

    [Association(Storage = "_Transactions", OtherKey="CustomerID")]
    public EntitySet<Transaction> Transactions
    {
        get { return this._Transactions; }
        set { this._Transactions.Assign(value); }
    }

    public Customer()
    {
        this._Transactions = new EntitySet<Transaction>();
    }
}

[Table(Name = "custtran")]
public class Transaction
{
    [Column(Name = "compno", DbType="smallint")]
    public int CompanyNumber { get; set; }

    [Column(IsPrimaryKey = true, Name = "tran_no")]
    public int TranNo { get; set; }

    [Column(Name = "customer_id")]
    public int CustomerID { get; set; }

    [Column(Name = "tran_type", DbType="char(4)")]
    public string TranType { get; set; }

    private EntityRef<Customer> _Customer;

    [Association(Storage = "_Customer", ThisKey = "CustomerID")]
    public Customer Customer
    {
        get { return this._Customer.Entity; }
        set { this._Customer.Entity = value; }
    }

    private EntitySet<TransactionType> _TransactionTypes;
    [Association(Name="Custtran_TranType", Storage = "_TransactionTypes", IsForeignKey=true,  OtherKey = "TranType")]
    public EntitySet<TransactionType> TransactionTypes
    {
        get { return this._TransactionTypes; }
        set { this._TransactionTypes.Assign(value); }
    }

    public Transaction()
    {
       this._Customer = default(EntityRef<Customer>);
       this._TransactionTypes = new EntitySet<TransactionType>();
    }
}

[Table(Name = "tran_type")]
public class TransactionType
{
    [Column(Name = "compno", DbType = "smallint")]
    public int CompanyNumber { get; set; }

    [Column(IsPrimaryKey = true, Name = "tran_type", DbType="char(4)")]
    public string TranType { get; set; }

    [Column(Name = "description", DbType="Varchar(50)")]
    public string Description { get; set; }

    private EntityRef<Transaction> _Transaction;
    [Association(Name="Custtran_TranType", Storage = "_Transaction", ThisKey = "TranType")]
    public Transaction Transaction
    {
        get { return this._Transaction.Entity; }
        set { this._Transaction.Entity = value; }
    }

    public TransactionType()
    {
        this._Transaction = default(EntityRef<Transaction>);
    }
}

Answer 1

忽略我，我已經回答了我自己的問題。

private EntitySet<TransactionType> _TransactionTypes;
    [Association(Name="Custtran_TranType", Storage = "_TransactionTypes", IsForeignKey=true, ThisKey="TranType", OtherKey = "TranType")]
    public EntitySet<TransactionType> TransactionTypes
    {
        get { return this._TransactionTypes; }
        set { this._TransactionTypes.Assign(value); }
    }

向協會添加了ThisKey，現在可以正常使用了。