ConnectionOpen

This event is triggered upon the OracleConnection.Open() method or a connection opening to undertake Application Continuity failover and replay.

Declaration

// C#
public event OracleConnectionOpenEventHandler ConnectionOpen;

Event Data

The event handler receives a OracleConnectionOpenEventArgs object which exposes the following property containing information about the ConnectionOpen event.

Connection

OracleConnection object on which Open() is called.

Exceptions

InvalidOperationException() - if CPVersion=1.0 and the ConnectionOpen event is used. Applies to unmanaged ODP.NET only.
InvalidOperationException() - if the ConnectionOpen event is set after opening a connection.

Remarks

This feature requires CPVersion=2.0 to be used.

In order to configure the connection before it is dispensed, the application should register the callback to the ConnectionOpen event before Open() is called.

Only supported for .NET Framework 4.x and .NET (Core).

Application Continuity Scenarios

For applications that set state only at the beginning of a request or for stateful applications that gain performance benefits from using connections with a preset state, they can register for a ConnectionOpen event and then check the reason for the event before taking appropriate action.

When registered, the event will be executed upon successful reconnection following a recoverable error. The triggering event reason will be available through ConnectionOpenReason property of OracleConnectionOpenEventArgs object provided with the event.

The application is responsible for ensuring the initialization actions are the same as that of the original connection before failover. If the event invocation fails, then replay is disabled on that connection.

Example

// C#
// NOTE: The sample below requires CPVersion=2.0 to be configured in the .NET configuration
using System;
using Oracle.ManagedDataAccess.Client;

class ConOpenEventSample
{
  public static void ConOpenCallback(OracleConnectionOpenEventArgs eventArgs)
  {
    OracleCommand cmd = new OracleCommand("ALTER SESSION SET NLS_LANGUAGE='GERMAN'", eventArgs.Connection);
    cmd.ExecuteNonQuery();
    cmd.Dispose();
  }

  static void Main(string[] args)
  {
    // Establish a connection
    string constr = "user id=hr;password=hr;data source=oracle";
    OracleConnection con = new OracleConnection(constr);
    con.ConnectionOpen += ConOpenCallback;
    con.Open();
    con.Dispose();
  }
}