MySQL和插入最後一個ID問題仍然

Question

確定後，大量的閱讀，並試圖我仍然不能似乎得到這個工作：

 OdbcCommand cmd = new OdbcCommand("INSERT INTO User (Email) VALUES ('rusty@msn.com'); SELECT LAST_INSERT_ID();", cn); 

cmd.ExecuteNonQuery(); 
       using (OdbcDataReader reader = cmd.ExecuteReader()) 
       { 

       string theUserId = String.Format("{0}", reader.GetString(0)); 
       Label10.Text = theUserId; 

表：

User 
-------- 
UserID (auto increment, pk) 
Email 

運行在調試模式下我上得到錯誤這條線，

  using (OdbcDataReader reader = cmd.ExecuteReader()) 

，並

cmd.ExecuteNonQuery(); 

Mysql在這一行上說它的語法錯誤SELECT LAST_INSERT_ID();"，cn）;但從什麼是閱讀這是合法的。

確切的錯誤：

ERROR [42000] [MySQL][ODBC 3.51 Driver][mysqld-5.5.9]You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT LAST_INSERT_ID()' at line 1 

編輯：Justins方法：

using (OdbcConnection connection = new OdbcConnection("Driver={MySQL ODBC 3.51 Driver}; Server=localhost; Database=gymwebsite2; User=root; Password=commando;")) 
{ 
    // ODBC command and transaction objects 
    OdbcCommand command = new OdbcCommand(); 
    OdbcTransaction transaction = null; 

    // tell the command to use our connection 
    command.Connection = connection; 

    try 
    { 
     // open the connection 
     connection.Open(); 

     // start the transaction 
     transaction = connection.BeginTransaction(); 

     // Assign transaction object for a pending local transaction. 
     command.Connection = connection; 
     command.Transaction = transaction; 

     // TODO: Build a SQL INSERT statement 
     OdbcCommand cmd = new OdbcCommand("INSERT INTO User (Email, FirstName, SecondName, DOB, Location, Aboutme, username, password) VALUES ('" + TextBox1.Text + "', '" + TextBox2.Text + "', '" + TextBox3.Text + "', '" + TextBox4.Text + "', '" + TextBox5.Text + "', '" + TextBox6.Text + "', '" + TextBox7.Text + "', '" + TextBox8.Text + "')", connection); 

     // run the insert using a non query call 
     command.CommandText = cmd.ToString(); 
     command.ExecuteNonQuery(); 

     /* now we want to make a second call to MYSQL to get the new index 
      value it created for the primary key. This is called using scalar so it will 
      return the value of the SQL statement. We convert that to an int for later use.*/ 
     command.CommandText = "select last_insert_id();"; 
     id = Convert.ToInt32(command.ExecuteScalar()); 

     // the name id doesnt not exist in the current context 

     // Commit the transaction. 
     transaction.Commit(); 
    } 
    catch (Exception ex) 
    { 
     Label10.Text = ": " + ex.Message; 

     try 
     { 
      // Attempt to roll back the transaction. 
      transaction.Rollback(); 
     } 
     catch 
     { 
      // Do nothing here; transaction is not active. 
     } 
    } 
} 

Answer 1

澄清，MySQL的.NET ODBC驅動程序不允許多個命令，就像你所描述的運行。您必須進行兩個獨立的呼叫並將其包裝在交易中。

// open a new connection using a default connection string I have defined elsewhere 
using(OdbcConnection connection = new OdbcConnection(s_connectionString)) 
{ 
     // ODBC command and transaction objects 
     OdbcCommand command = new OdbcCommand(); 
     OdbcTransaction transaction = null; 

     // tell the command to use our connection 
     command.Connection = connection; 

     try 
     { 
      // open the connection 
      connection.Open(); 

      // start the transaction 
      transaction = connection.BeginTransaction(); 

      // Assign transaction object for a pending local transaction. 
      command.Connection = connection; 
      command.Transaction = transaction; 

      // TODO: Build a SQL INSERT statement 
      StringBuilder SQL = new StringBuilder(); 

      // run the insert using a non query call 
      command.CommandText = SQL.ToString(); 
      command.ExecuteNonQuery(); 

      /* now we want to make a second call to MYSQL to get the new index 
       value it created for the primary key. This is called using scalar so it will 
       return the value of the SQL statement. We convert that to an int for later use.*/ 
      command.CommandText = "select last_insert_id();"; 
      id = Convert.ToInt32(command.ExecuteScalar()); 

      // Commit the transaction. 
      transaction.Commit(); 
    } 
    catch(Exception ex) 
    { 
      Debug.WriteLine(ex.Message); 

      try 
      { 
       // Attempt to roll back the transaction. 
       transaction.Rollback(); 
      } 
      catch 
      { 
       // Do nothing here; transaction is not active. 
       } 
     } 
} 

Answer 2

如果你的電子郵件是唯一可以使用

Select ID From User where Email='rusty@msn.com' 

你確信你總是得到正確的答案。

如果你的電子郵件是不是唯一的，你應該使用鎖，以確保只有線程執行查詢，然後將您的插入後，使用此查詢

Select Max(ID) From User 

Answer 3

一種解決方法：

1. 添加out param to your query：
2. 查詢內部使用SET @OpParam = SELECT LAST_INSERT_ID（）;
3. 在你的代碼中，如果（（int）@ OpParam.Value> 0）{pull out}。
4. 此外，如果運行選擇，則改爲NonQuery，使用ExecuteScalar（）。

希望它可以幫助你。