Rollback() Method

In This Topic

Rolls back a database transaction from a pending state.

Syntax

Visual Basic
C#

'Declaration
 
Public Overloads 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 PgSqlConnection.BeginTransaction has been called, but before Commit is called).

Example

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

csharp

public void RunPgSqlTransaction(string myConnString)
{
  PgSqlConnection pgConnection = new PgSqlConnection(myConnString);
  pgConnection.Open();

  PgSqlCommand pgCommand = new PgSqlCommand();
  PgSqlTransaction myTrans;

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

  try
  {
    pgCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(50, 'DEVELOPMENT')";
    pgCommand.ExecuteNonQuery();
    pgCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(60, 'PRODUCTION')";
    pgCommand.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
  {
    pgConnection.Close();
  }
}

Visual Basic

Public Sub RunPgSqlTransaction(myConnString As String)
  Dim pgConnection As New PgSqlConnection(myConnString)
  pgConnection.Open()

  Dim pgCommand As New PgSqlCommand()
  Dim myTrans As PgSqlTransaction

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

  Try
    pgCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(50, 'DEVELOPMENT')"
    pgCommand.ExecuteNonQuery()
    pgCommand.CommandText = "INSERT INTO Test.Dept(DeptNo, DName) Values(60, 'PRODUCTION')"
    pgCommand.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
    pgConnection.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

PgSqlTransaction Class
PgSqlTransaction Members
Overload List
BeginTransaction Method
Commit Method
Save Method

Send Feedback