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<docs>
<Class>
<summary>
Represents a SQL transaction to be made in a MySQL database. This class cannot be inherited.
</summary>
<remarks>
The application creates a <B>MySqlTransaction</B> object by calling <see cref="MySqlConnection.BeginTransaction()"/>
on the <see cref="MySqlConnection"/> object. All subsequent operations associated with the
transaction (for example, committing or aborting the transaction), are performed on the
<B>MySqlTransaction</B> object.
</remarks>
<example>
The following example creates a <see cref="MySqlConnection"/> and a <B>MySqlTransaction</B>.
It also demonstrates how to use the <see cref="MySqlConnection.BeginTransaction()"/>,
<see cref="MySqlTransaction.Commit"/>, and <see cref="MySqlTransaction.Rollback"/> methods.
<code lang="vbnet">
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 Region (RegionID, RegionDescription) VALUES (100, 'Description')"
myCommand.ExecuteNonQuery()
myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) 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 'RunTransaction
</code>
<code lang="C#">
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 Region (RegionID, RegionDescription) VALUES (100, 'Description')";
myCommand.ExecuteNonQuery();
myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')";
myCommand.ExecuteNonQuery();
myTrans.Commit();
Console.WriteLine("Both records are written to database.");
}
catch(Exception e)
{
try
{
myTrans.Rollback();
}
catch (MySqlException 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();
}
}
</code>
</example>
</Class>
<Rollback>
<summary>
Rolls back a transaction from a pending state.
</summary>
<remarks>
The Rollback method is equivalent to the MySQL statement ROLLBACK.
The transaction can only be rolled back from a pending state
(after BeginTransaction has been called, but before Commit is
called).
</remarks>
<example>
The following example creates a <see cref="MySqlConnection"/> and a
<see cref="MySqlTransaction"/>. It also demonstrates how to use the
<see cref="MySqlConnection.BeginTransaction()"/>, <see cref="Commit"/>, and <B>Rollback</B>
methods.
<code lang="vbnet">
Public Sub RunSqlTransaction(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 mytable (id, desc) VALUES (100, 'Description')"
myCommand.ExecuteNonQuery()
myCommand.CommandText = "Insert into mytable (id, desc) VALUES (101, 'Description')"
myCommand.ExecuteNonQuery()
myTrans.Commit()
Console.WriteLine("Success.")
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
</code>
<code lang="C#">
public void RunSqlTransaction(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 mytable (id, desc) VALUES (100, 'Description')";
myCommand.ExecuteNonQuery();
myCommand.CommandText = "Insert into mytable (id, desc) VALUES (101, 'Description')";
myCommand.ExecuteNonQuery();
myTrans.Commit();
Console.WriteLine("Both records are written to database.");
}
catch(Exception e)
{
try
{
myTrans.Rollback();
}
catch (MySqlException 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();
}
}
</code>
</example>
</Rollback>
<Commit>
<summary>
Commits the database transaction.
</summary>
<remarks>
The <b>Commit</b> method is equivalent to the MySQL SQL statement
COMMIT.
</remarks>
<example>
The following example creates a <see cref="MySqlConnection"/> and a
<see cref="MySqlTransaction"/>. It also demonstrates how to use the
<see cref="MySqlConnection.BeginTransaction()"/>, <see cref="Commit"/>, and <B>Rollback</B>
methods.
<code lang="vbnet">
Public Sub RunSqlTransaction(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 mytable (id, desc) VALUES (100, 'Description')"
myCommand.ExecuteNonQuery()
myCommand.CommandText = "Insert into mytable (id, desc) VALUES (101, 'Description')"
myCommand.ExecuteNonQuery()
myTrans.Commit()
Console.WriteLine("Success.")
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
</code>
<code lang="C#">
public void RunSqlTransaction(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 mytable (id, desc) VALUES (100, 'Description')";
myCommand.ExecuteNonQuery();
myCommand.CommandText = "Insert into mytable (id, desc) VALUES (101, 'Description')";
myCommand.ExecuteNonQuery();
myTrans.Commit();
Console.WriteLine("Both records are written to database.");
}
catch(Exception e)
{
try
{
myTrans.Rollback();
}
catch (MySqlException 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();
}
}
</code>
</example>
</Commit>
</docs>
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