BeginTransaction Method (IsolationLevel)

MySQL Connector/Net

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Visual C++

MySQL Connector/Net

MySqlConnection..::.BeginTransaction Method (IsolationLevel)

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Begins a database transaction with the specified isolation level.

Namespace: MySql.Data.MySqlClient
Assembly: MySql.Data (in MySql.Data.dll) Version: 6.2.2.0

Syntax

C#
public MySqlTransaction BeginTransaction( IsolationLevel iso )

Visual Basic (Declaration)
Public Function BeginTransaction ( _ iso As IsolationLevel _ ) As MySqlTransaction

Visual C++
public: MySqlTransaction^ BeginTransaction( IsolationLevel iso )

Parameters

iso: Type: System.Data..::.IsolationLevel
The isolation level under which the transaction should run.

Return Value

An object representing the new transaction.

Remarks

This command is equivalent to the MySQL BEGIN TRANSACTION command.

You must explicitly commit or roll back the transaction using the Commit()()() or Rollback()()() method.

Note: If you do not specify an isolation level, the default isolation level is used. To specify an isolation level with the BeginTransaction()()() method, use the overload that takes the iso parameter. Also note that any attempt to begin a transaction while a transaction is in progress will throw an exception on MySQL 4.1 and higher. On MySQL 4.0, an exception will not be thrown because servers 4.0 and earlier did not report their transacation status.

Examples

The following example creates a MySqlConnection and a MySqlTransaction. It also demonstrates how to use the BeginTransaction, a Commit()()(), and Rollback()()() methods.

CopyVB.NET

Public Sub RunTransaction(myConnString As String)
Dim myConnection As New MySqlConnection(myConnString)
myConnection.Open()

Dim myCommand As MySqlCommand = myConnection.CreateCommand()
Dim myTrans As MySqlTransaction

' Start a local transaction
myTrans = myConnection.BeginTransaction()
' Must assign both transaction object and connection
' to Command object for a pending local transaction
myCommand.Connection = myConnection
myCommand.Transaction = myTrans

Try
myCommand.CommandText = "Insert into Test (id, desc) VALUES (100, 'Description')"
myCommand.ExecuteNonQuery()
myCommand.CommandText = "Insert into Test (id, desc) VALUES (101, 'Description')"
myCommand.ExecuteNonQuery()
myTrans.Commit()
Console.WriteLine("Both records are written to database.")
Catch e As Exception
Try
myTrans.Rollback()
Catch ex As MySqlException
If Not myTrans.Connection Is Nothing Then
Console.WriteLine("An exception of type " + ex.GetType().ToString() + _
" was encountered while attempting to roll back the transaction.")
End If
End Try

Console.WriteLine("An exception of type " + e.GetType().ToString() + _
"was encountered while inserting the data.")
Console.WriteLine("Neither record was written to database.")
Finally
myConnection.Close()
End Try
End Sub

CopyC#

public void RunTransaction(string myConnString)
{
MySqlConnection myConnection = new MySqlConnection(myConnString);
myConnection.Open();

MySqlCommand myCommand = myConnection.CreateCommand();
MySqlTransaction myTrans;

// Start a local transaction
myTrans = myConnection.BeginTransaction();
// Must assign both transaction object and connection
// to Command object for a pending local transaction
myCommand.Connection = myConnection;
myCommand.Transaction = myTrans;

try
{
myCommand.CommandText = "insert into Test (id, desc) VALUES (100, 'Description')";
myCommand.ExecuteNonQuery();
myCommand.CommandText = "insert into Test (id, desc) VALUES (101, 'Description')";
myCommand.ExecuteNonQuery();
myTrans.Commit();
Console.WriteLine("Both records are written to database.");
}
catch(Exception e)
{
try
{
myTrans.Rollback();
}
catch (SqlException ex)
{
if (myTrans.Connection != null)
{
Console.WriteLine("An exception of type " + ex.GetType() +
" was encountered while attempting to roll back the transaction.");
}
}

Console.WriteLine("An exception of type " + e.GetType() +
" was encountered while inserting the data.");
Console.WriteLine("Neither record was written to database.");
}
finally
{
myConnection.Close();
}
}

Exceptions

Exception	Condition
System..::.InvalidOperationException	Parallel exceptions are not supported.