PgDatabase

#include <iostream.h>
#include "libpq++.h"

int main()
{
  // Open the connection to the database and make sure it's OK
  PgDatabase data("dbname=template1");
  if ( data.ConnectionBad() ) {
      cout << "Connection was unsuccessful..." << endl
           << "Error message returned: " << data.ErrorMessage() << endl;
      return 1;
  }
  else
      cout << "Connection successful... Enter queries below:" << endl;
    
  // Interactively obtain and execute queries
  ExecStatusType status;
  string buf;
  int done = 0;
  while (!done)
    {
      cout << "> ";
      cout.flush();
      getline(cin, buf);
      if ( buf != "" )
            if ( (status = data.Exec( buf.c_str() )) 
                == PGRES_TUPLES_OK ) 
                data.DisplayTuples();
            else
                cout << "No tuples returned..." << endl
                     << "status = " << status << endl
                     << "Error returned: " 
                     << data.ErrorMessage() << endl;
      else
               done = 1;
      }
  return 0;
} // End main()

#include <iostream.h>
#include <iomanip.h>
#include "libpq++.h"

int main()
{
  // Begin, by establishing a connection to the backend.
  // When no parameters are given then the system will
  // try to use reasonable defaults by 
  // looking up environment variables 
  // or, failing that, using hardwired constants
  const char* dbName = "dbname=template1";
  PgDatabase data(dbName);

  // check to see that the backend connection 
  // was successfully made
  if ( data.ConnectionBad() ) {
      cerr << "Connection to database '" 
           << dbName << "' failed." << endl
           << "Error returned: " 
           << data.ErrorMessage() << endl;
      exit(1);
  }

  // start a transaction block
  if ( !data.ExecCommandOk("BEGIN") ) {
    cerr << "BEGIN command failed" << endl;
    exit(1);
  }

  // submit command to the backend
  if ( !data.ExecCommandOk("DECLARE myportal CURSOR 
    FOR select * from pg_database") ) {
    cerr << "DECLARE CURSOR command failed" << endl;
    exit(1);
  }

  // fetch instances from the pg_database, 
  // the system catalog of databases
  if ( !data.ExecTuplesOk("FETCH ALL in myportal") ) {
    cerr << "FETCH ALL didn't return tuples properly" << endl;
    exit(1);
  }
 
  // first, print out the attribute names
  int nFields = data.Fields();
  for (int i=0; i < nFields; i++)
      cout << setiosflags(ios::right) 
           << setw(15) << data.FieldName(i);
  cout << endl << endl;

  // next, print out the instances
  for (int i=0; i < data.Tuples(); i++) {
       for (int j=0; j < nFields; j++)
            cout << setiosflags(ios::right) 
                 << setw(15) << data.GetValue(i,j);
       cout << endl;
  }

  // Close the portal
  data.Exec("CLOSE myportal");

  // End the transaction
  data.Exec("END");
  return 0;
}

CREATE TABLE TBL1 (i int4);

CREATE TABLE TBL2 (i int4);

CREATE RULE r1 AS ON INSERT TO TBL1 DO 
 [INSERT INTO TBL2 values (new.i); NOTIFY TBL2];

INSERT INTO TBL1 VALUES (10);

#include <iostream.h>
#include "libpq++.h"
#include <stdlib.h>

main()
{
  // Begin, by connecting to the backend using 
  // hardwired constants and a test database 
  // created by the user prior to the invocation
  // of this test program.
  char* dbName = "dbname=template1";
  PgDatabase data(dbName);

  // Check to see that the backend connection 
  // was successfully made
  if ( data.ConnectionBad() ) {
    cerr << "Connection to database '" 
         << dbName << "' failed." << endl
         << data.ErrorMessage() << endl;
    exit(1);
  }

  // Listen to a table
  if ( !data.ExecCommandOk("LISTEN TBL2") ) {
    cerr << "LISTEN command failed" << endl;
    exit(1);
  }

  // Test asynchronous notification
  while (1) {
      // check for asynchronous returns
      PGnotify* notify = data.Notifies();
      if (notify) {
         cerr << "ASYNC NOTIFY of '" << notify->relname 
               << "' from backend pid '" << notify->be_pid 
               << "' received" << endl;
          free(notify);
          break;
      }
  }
  return 0;
}