如何在c＃中使用sqltransaction

我正在使用以下代码一次执行两个命令。 我使用sqltransaction来确保所有命令都被执行或回滚。当我运行没有“事务”的程序时它运行正常但是当我使用“事务”时它们显示错误。 我的代码如下;

SqlTransaction transaction = connectionsql.BeginTransaction(); try { SqlCommand cmd1 = new SqlCommand("select account_name from master_account where NOT account_name = 'BANK' AND NOT account_name = 'LOAN'", connectionsql); SqlDataReader dr1 = cmd1.ExecuteReader(); while (dr1.Read()) { comboBox1.Items.Add(dr1[0].ToString().Trim()); } cmd1.Dispose(); dr1.Dispose(); SqlCommand cmd2 = new SqlCommand("select items from rate",connectionsql); SqlDataReader dr2 = cmd2.ExecuteReader(); while (dr2.Read()) { comboBox2.Items.Add(dr2[0].ToString().Trim()); } cmd2.Dispose(); dr2.Dispose(); transaction.Commit(); dateTimePicker4.Value = dateTimePicker3.Value; } catch(Exception ex) { transaction.Rollback(); MessageBox.Show(ex.ToString()); } 

和错误：

Answer 1

您必须告诉您的SQLCommand对象使用该事务：

 cmd1.Transaction = transaction; 

或者在构造函数中：

 SqlCommand cmd1 = new SqlCommand("select...", connectionsql, transaction); 

确保也打开了connectionsql对象。

但你所做的只是SELECT语句。 使用INSERT，UPDATE等类型操作时，事务将受益更多。

Answer 2

以下示例创建SqlConnection和SqlTransaction。 它还演示了如何使用BeginTransaction，Commit和Rollback方法。 事务在任何错误时回滚，或者在没有首先提交的情况下处理它。 Try / Catcherror handling用于在尝试提交或回滚事务时处理任何错误。

 private static void ExecuteSqlTransaction(string connectionString) { using (SqlConnection connection = new SqlConnection(connectionString)) { connection.Open(); SqlCommand command = connection.CreateCommand(); SqlTransaction transaction; // Start a local transaction. transaction = connection.BeginTransaction("SampleTransaction"); // Must assign both transaction object and connection // to Command object for a pending local transaction command.Connection = connection; command.Transaction = transaction; try { command.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')"; command.ExecuteNonQuery(); command.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')"; command.ExecuteNonQuery(); // Attempt to commit the transaction. transaction.Commit(); Console.WriteLine("Both records are written to database."); } catch (Exception ex) { Console.WriteLine("Commit Exception Type: {0}", ex.GetType()); Console.WriteLine(" Message: {0}", ex.Message); // Attempt to roll back the transaction. try { transaction.Rollback(); } catch (Exception ex2) { // This catch block will handle any errors that may have occurred // on the server that would cause the rollback to fail, such as // a closed connection. Console.WriteLine("Rollback Exception Type: {0}", ex2.GetType()); Console.WriteLine(" Message: {0}", ex2.Message); } } } } 

请参见SqlTransaction类

Answer 3

好吧，我不明白你为什么在做出select时使用交易。

当您从数据库进行更改（添加，编辑或删除）数据时，事务非常有用。

除非使用insert ， update或delete语句，否则删除事务

Answer 4

您可以从SqlConnection创建SqlTransaction 。

并使用它来创建任意数量的SqlCommands

 SqlTransaction transaction = connection.BeginTransaction(); var cmd1 = new SqlCommand(command1Text, connection, transaction); var cmd2 = new SqlCommand(command2Text, connection, transaction); 

要么

 var cmd1 = new SqlCommand(command1Text, connection, connection.BeginTransaction()); var cmd2 = new SqlCommand(command2Text, connection, cmd1.Transaction); 

---

如果命令失败从未导致意外更改， 请不要使用事务。

如果命令失败可能导致意外更改，则将它们放入Try / Catch块并在另一个 Try / Catch块中回滚该操作。

根据MSDN ：

回滚事务时应始终使用 Try / Catchexception处理。 如果连接终止或者事务已在服务器上回滚，则Rollback会生成InvalidOperationException 。

这是一个示例代码：

 string connStr = "[connection string]"; string cmdTxt = "[t-sql command text]"; using (var conn = new SqlConnection(connStr)) { conn.Open(); var cmd = new SqlCommand(cmdTxt, conn, conn.BeginTransaction()); try { cmd.ExecuteNonQuery(); //before this line, nothing has happened yet cmd.Transaction.Commit(); } catch(System.Exception ex) { //You should always use a Try/Catch for transaction's rollback try { cmd.Transaction.Rollback(); } catch(System.Exception ex2) { throw ex2; } throw ex; } conn.Close(); } 

如果事务在调用Commit或Rollback之前处理，则事务将回滚。

因此，您无需担心应用程序被关闭。

Answer 5

使用sql事务更新或删除

  private void SQLTransaction() { try { string sConnectionString = "My Connection String"; string query = "UPDATE [dbo].[MyTable] SET ColumnName = '{0}' WHERE ID = {1}"; SqlConnection connection = new SqlConnection(sConnectionString); SqlCommand command = connection.CreateCommand(); connection.Open(); SqlTransaction transaction = connection.BeginTransaction(""); command.Transaction = transaction; try { foreach(DataRow row in dt_MyData.Rows) { command.CommandText = string.Format(query, row["ColumnName"].ToString(), row["ID"].ToString()); command.ExecuteNonQuery(); } transaction.Commit(); } catch (Exception ex) { transaction.Rollback(); MessageBox.Show(ex.Message, "Error"); } } catch (Exception ex) { MessageBox.Show("Problem connect to database.", "Error"); } } 

Answer 6

首先，您不需要事务，因为您只是查询select语句，因为它们都是select语句，您可以将它们组合成一个由空格分隔的查询，并使用数据集来获取所有检索的表。 这种方式更好，因为您只对数据库进行了一次事务，因为数据库事务很昂贵，因此您的代码更快。 第二个人真的必须使用事务，只需将事务分配给SqlCommand就好了

 sqlCommand.Transaction = transaction; 

并且只使用一个SqlCommand不要声明多个，因为变量占用空间，我们也在使代码更高效的主题上，通过将commandText分配给不同的查询字符串并像执行它们一样执行它们

 sqlCommand.CommandText = "select * from table1"; sqlCommand.ExecuteNonQuery(); sqlCommand.CommandText = "select * from table2"; sqlCommand.ExecuteNonQuery();