occitaf.cpp

occi在oralce10G中的两个例子

/*
        Name
          tafdemo.cpp - OCCI TAF Demo
        
        Description
          Demo of OCCI TAF Feature. 
          1. Select few records from the emp table in scott user.
          2. The user is prompted to bounce the server.
          3. Failover is attempted and the rest of the records
          are fetched after failover.

*/

#include<occi.h>
#include<stdio.h>
#include<iostream>
using namespace oracle::occi;
using namespace std;

int taf_callback(Environment *env, Connection *conn, void *ctx,  \
Connection::FailOverType foType, Connection::FailOverEventType foEvent)
{
  cout << "[Callback] Called " << endl;

  cout << "Failover Event : " ;
  switch(foEvent)
  {
     case Connection::FO_END   : cout << "FO_END" << endl;
                                 break;
     case Connection::FO_ABORT : cout << "FO_ABORT" << endl;
                                 break;
     case Connection::FO_REAUTH: cout << "FO_REAUTH" << endl;
                                 break;
     case Connection::FO_BEGIN : cout << "FO_BEGIN" << endl;
                                 break;
     case Connection::FO_ERROR : cout << "FO_ERROR" << endl;
                                 break;
     default                   : cout << "Default " << endl;
                                 break;
  }  
  cout << "Failover Type : " ;
  switch(foType)
  {
     case Connection::FO_NONE   : cout << "FO_NONE" << endl;
                                  break;
     case Connection::FO_SESSION: cout << "FO_SESSION" << endl;
                                  break;
     case Connection::FO_SELECT : cout << "FO_SELECT" << endl;
                                  break;
     default                    : cout << "Default " << endl;
                                  break;
  }
  if (foEvent == Connection::FO_ERROR)
    return FO_RETRY;
  if (foEvent == Connection::FO_END)
  {
    cout << "Failover complete" << endl;
    return 0;
  }
  return 0;
}

/**
 * The main function 
 */
int main (ub4 argc, char* argv[])
{
   Environment *env;
   Connection *conn;
   string userName ;
   string password ; 
   string database ;
   try
   {
      /*Connect String (database variable) should be
        failover configured for TAF to work correctly.*/

      userName="SCOTT";
      password="TIGER";
      database="mydb";

  
      /* Example of Failover Configured String:  This should be the way
         the connect string should be configured for failover.
         mydb      = (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=hostname)\
         (PORT=portno))(CONNECT_DATA=(SERVICE_NAME=svcname)
         (FAILOVER_MODE=(TYPE=SELECT)(METHOD=BASIC))))
       */
 

      /*Creating the OCCI Environment and Creating a 
        connection to the Scott User */
    
      cout << "OCCI Demo Of TAF" << endl;

      env=Environment::createEnvironment(Environment::DEFAULT);
      conn=env->createConnection(userName,password,database);
      cout << "OCCI Environment  and Connection Created " << endl;
   
      //Registering the Connection for TAF Callback.
      cout << "Registering the Connection with the TAF Callback" << endl;
      conn->setTAFNotify(taf_callback,NULL);
    }catch(SQLException &e)
    {
      cout << "Error in Constructor Call " << endl;
      cout << "Error Number: " << e.getErrorCode() << endl;
      cout << e.getMessage() << endl;
    }
    try
    {
      int idx=0;
      int c1;
      int ch;
      string c2;

      Statement *stmt = conn->createStatement("SELECT empno, ename \
      FROM emp ORDER BY empno");

      cout << "Selecting Records from Emp Table " << endl;
      ResultSet *rs = stmt->executeQuery();

      /*The logic is as follows.
        A select statement is issued to the server. After 2 records are
        fetched the server is bounced. This triggers the failover 
        and the rest of the records are fetched after the failover*/

      while(idx++ < 2)
      {
        rs->next();
        c1=rs->getInt(1);
        c2=rs->getString(2);
        cout <<"Emp No   :" << c1 << endl;
        cout <<"Emp Name :" << c2 << endl;
      }
      cout << "Fetched Partial Number of Records " << endl;
      cout << "Performing Failover" << endl;

      /*The callback gets called whenever the failover is 
        attemped for this connection since the callback is
        registered with the connection.  
        Hence if the application tries to fail over even before 
        the instance is brought up the failover would be attempted 
        and callback called and FO_ERROR would be raised.
        In the callback whenever an FO_ERROR is recieved, FO_RETRY is sent. 
        The failover would be attempted until the instance is 
        actually brought up which is when FO_END would be signalled 
        and the failover would succeed*/
    
      cout << "Bounce the Server" << endl;
      cout << "Once the Server is brought up. Press any key to continue" << endl;
      fflush(stdin);
      ch=getchar();
      try
      {
        cout << "Connection About to Fail Over" << endl;
        while(rs->next())
        {
          c1=rs->getInt(1);
          c2=rs->getString(2);
          cout <<"Emp No   :" << c1 << endl;
          cout <<"Emp Name :" << c2 << endl;
        }
        cout << "Selected All Rows after failover" << endl;
      }catch (SQLException &e)
      {
        cout << "Error during Selecting rest of the rows" << endl;
        cout << "Error Number: " << e.getErrorCode() << endl;
        cout << e.getMessage() << endl;
      }
      stmt->closeResultSet(rs);
      conn->terminateStatement(stmt);
    }catch (SQLException &e)
    {
      cout << "Exception " << endl;
      cout << "Error Number: " << e.getErrorCode() << endl;
      cout << e.getMessage() << endl;
    }

    //Terminating the Connection and the OCCI Environment
    cout << "Terminating the Connection and The Environment" << endl;
    env->terminateConnection(conn);
    Environment::terminateEnvironment(env);

    cout << "Demo Done" << endl;
}