Rollback Method (UniTransaction)

In This Topic

Rolls back a database transaction from a pending state.

Syntax

Visual Basic
C#

'Declaration
 
Public Overrides Sub Rollback()

public override void Rollback()

Remarks

The Rollback method is equivalent to the SQL ROLLBACK statement. The transaction can only be rolled back from a pending state (after UniConnection.BeginTransaction has been called, but before Commit is called).

Example

The following example creates a UniConnection and a UniTransaction. It also demonstrates how to use the UniConnection.BeginTransaction, Commit, and Rollback methods.

csharp

public void RunUniTransaction(string myConnString)
{
  UniConnection myConnection = new UniConnection(myConnString);
  myConnection.Open();

  UniCommand myCommand = new UniCommand();
  UniTransaction myTrans;

  // Start a local transaction
  myTrans = myConnection.BeginTransaction();
  // Assign transaction object for a pending local transaction
  myCommand.Transaction = myTrans;

  try
  {
    myCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(50, 'DEVELOPMENT')";
    myCommand.ExecuteNonQuery();
    myCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(60, 'PRODUCTION')";
    myCommand.ExecuteNonQuery();
    myTrans.Commit();
    Console.WriteLine("Both records are written to database.");
  }
  catch(Exception e)
  {
    myTrans.Rollback();
    Console.WriteLine(e.ToString());
    Console.WriteLine("Neither record was written to database.");
  }
  finally
  {
    myConnection.Close();
  }
}

Visual Basic

Public Sub RunUniTransaction(myConnString As String)
  Dim myConnection As New UniConnection(myConnString)
  myConnection.Open()

  Dim myCommand As New UniCommand()
  Dim myTrans As UniTransaction

  ' Start a local transaction
  myTrans = myConnection.BeginTransaction()
  ' Assign transaction object for a pending local transaction
  myCommand.Transaction = myTrans

  Try
    myCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(50, 'DEVELOPMENT')"
    myCommand.ExecuteNonQuery()
    myCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(60, 'PRODUCTION')"
    myCommand.ExecuteNonQuery()
    myTrans.Commit()
    Console.WriteLine("Both records are written to database.")
  Catch e As Exception
    myTrans.Rollback()
    Console.WriteLine(e.ToString())
    Console.WriteLine("Neither record was written to database.")
  Finally
    myConnection.Close()
  End Try
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

UniTransaction Class
UniTransaction Members
BeginTransaction Method
Commit Method

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