Wcf Rest服务中的SQL查询到Linq查询

Question

我将一个sql Transcation查询转换为Linq查询。我已经做了一点点，我试图写其余的linq查询，但我很困惑。

这是ADO.NET代码与Sql查询。

public bool RewardToCurrentTranscation(MoneyTransfer mopneyTransfer) 
     { 
      int amount = System.Convert.ToInt32(mopneyTransfer.Amount); 
      int amount1 = System.Convert.ToInt32(mopneyTransfer.Amount1); 

      SqlConnection cn = new SqlConnection(ConnectionString); 
      string sql = "select Account_Balance from Reward_Account_Details where Account_Number='" + mopneyTransfer.Sender_Account_No + "'"; 

      SqlCommand cmd = new SqlCommand(sql, cn); 
      if (cn.State == ConnectionState.Closed) 
       cn.Open(); 

      //amount = int.Parse(cmd.ExecuteScalar().ToString()); 

      if (amount > 0) 
      { 
       int b; 
       int b1; 
       SqlCommand cmd1 = new SqlCommand(); 
       SqlTransaction trans; 
       if (cn.State == ConnectionState.Closed) 
        cn.Open(); 
       trans = cn.BeginTransaction(); 

       cmd1.Connection = cn; 
       cmd1.CommandType = CommandType.Text; 
       cmd1.Transaction = trans; 
       cmd1.CommandText = "update Reward_Account_Details set Account_Balance=Account_Balance-'" + mopneyTransfer.Amount + "' where Account_Number='" + mopneyTransfer.Sender_Account_No + "'"; 
       b = cmd1.ExecuteNonQuery(); 

       cmd1.CommandText = "update Current_Account_Details set Account_Balance=Account_Balance+'" + mopneyTransfer.Amount1 + "' where Account_Number='" + mopneyTransfer.Receiver_Account_No + "'"; 
       b1 = cmd1.ExecuteNonQuery(); 
       if (b == 1 && b1 == 1) 
       { 
        trans.Commit(); 
        using (SqlConnection con = new SqlConnection(ConnectionString)) 
        { 
         //Create the SqlCommand object 
         //Create the SqlCommand object 
         SqlCommand cmd3 = new SqlCommand("Reward_Account_Wdraw", con); 
         //Specify that the SqlCommand is a stored procedure 
         cmd3.CommandType = System.Data.CommandType.StoredProcedure; 

         //Add the input parameters to the command object 
         cmd3.Parameters.AddWithValue("@Account_Number", mopneyTransfer.Sender_Account_No); 
         cmd3.Parameters.AddWithValue("@Account_Holder_Name", mopneyTransfer.Sender_Name); 
         cmd3.Parameters.AddWithValue("@Amount", mopneyTransfer.Amount); 


         cmd3.Parameters.AddWithValue("@Sort_Code", mopneyTransfer.Sender_Sort_Code); 
         cmd3.Parameters.AddWithValue("@Transcation_Type", mopneyTransfer.Transcation_Type); 
         cmd3.Parameters.AddWithValue("@Date", mopneyTransfer.Date); 

         SqlCommand cmd2 = new SqlCommand("Current_Account_Dposit", con); 
         //Specify that the SqlCommand is a stored procedure 
         cmd2.CommandType = System.Data.CommandType.StoredProcedure; 

         //Add the input parameters to the command object 
         cmd2.Parameters.AddWithValue("@Account_Number", mopneyTransfer.Receiver_Account_No); 
         cmd2.Parameters.AddWithValue("@Account_Holder_Name", mopneyTransfer.Receiver_Name); 
         cmd2.Parameters.AddWithValue("@Amount", mopneyTransfer.Amount1); 


         cmd2.Parameters.AddWithValue("@Sort_Code", mopneyTransfer.Receiver_Sort_Code); 
         cmd2.Parameters.AddWithValue("@Transcation_Type", mopneyTransfer.Transcation_Type1); 
         cmd2.Parameters.AddWithValue("@Date", mopneyTransfer.Date1); 




         //Open the connection and execute the query 

         con.Open(); 
         cmd2.ExecuteNonQuery(); 

         cmd3.ExecuteNonQuery(); 
         return true; 
         //con.Close(); 
        } 

       } 
       else 
        trans.Rollback(); 
       return false; 
      } 
      return false; 
     } 

到目前为止，我已经做了这么多的LINQ ...

public bool MoneyTranfer(MoneyTransfer mopneyTransfer) 
    { 


     int i = Convert.ToInt32(mopneyTransfer.Amount); 
     int j = Convert.ToInt32(mopneyTransfer.Amount1); 

     using (HalifaxDatabaseEntities ctx = new HalifaxDatabaseEntities()) 
     { 

      var foundAccount = (from a in ctx.Current_Account_Details where a.Account_Number.Equals(mopneyTransfer.Sender_Account_No) 
           select a).Distinct().FirstOrDefault(); 

      using (var dbContextTransaction = ctx.Database.BeginTransaction()) 
      { 
       var acctDetails = (from a in ctx.Current_Account_Details 
            where a.Account_Number.Equals(mopneyTransfer.Sender_Account_No) 
            select a).Distinct().FirstOrDefault(); 

       if (acctDetails != null) 
       { 
        ctx.SaveChanges(); 
        dbContextTransaction.Commit(); 
         } 
       else 
       { 
        dbContextTransaction.Rollback(); 
        return false; 
       } 
      } 

     } 
    } 

我对这个代码混淆..

cmd1.CommandText = "update Reward_Account_Details set Account_Balance=Account_Balance-'" + mopneyTransfer.Amount + "' where Account_Number='" + mopneyTransfer.Sender_Account_No + "'"; 

任何一个可以帮助我如何完成在linq中查询的其余部分

Answer 1

在你使用的内部，你应该发出这样的另一个查询：

var rewardAccount = ctx.Reward_Account_Details 
    .Where(r => r.Account_Number = moneyTransfer.Sender_Account_No) 
    .FirstOrDefault(); 

rewardAccount.Account_Balance -= moneyTransfer.Ammount; 

既然你有从HalifaxDatabaseEntities上下文Reward_Account_Details，调用的SaveChanges将节省这种变化也。

编辑

你并不需要显式地打开一个事务。 EF会自动为你做。请参阅以下代码并将其编辑为您的要求。

public bool MoneyTranfer(MoneyTransfer mopneyTransfer) 
{ 
    int i = Convert.ToInt32(mopneyTransfer.Amount); 
    int j = Convert.ToInt32(mopneyTransfer.Amount1); 

    try 
    { 
     using (HalifaxDatabaseEntities ctx = new HalifaxDatabaseEntities()) 
     { 
      var foundAccount = (from a in ctx.Current_Account_Details where a.Account_Number.Equals(mopneyTransfer.Sender_Account_No) 
           select a).Distinct().FirstOrDefault(); 

      var acctDetails = (from a in ctx.Current_Account_Details 
           where a.Account_Number.Equals(mopneyTransfer.Sender_Account_No) 
           select a).Distinct().FirstOrDefault(); 

      if(acctDetails == null) 
       return false; 

      var rewardAccount = ctx.Reward_Account_Details 
       .Where(r => r.Account_Number = moneyTransfer.Sender_Account_No) 
       .FirstOrDefault(); 

      rewardAccount.Account_Balance -= moneyTransfer.Ammount; 

      ctx.SaveChanges(); 

      return true; 
     } 
    } 
    catch(Exception) 
    { 
     //Maybe log it. 
    } 
    return false; 
}