C++ (LIBPQ++)

LIBPQ++ is POSTGRESQL's C++ interface. Figure  shows our application using this interface.  

        
        /*
         *  libpq++ sample program
         */
         
        #include <iostream.h>
        #include <libpq++.h>                                    // libpq++ header file
         
        int main()
        {
            char        state_code[3];                          // holds state code entered by user
            char        query_string[256];                      // holds constructed SQL query
            PgDatabase data("dbname=test");                     // connects to the database
         
            if ( data.ConnectionBad() )                         // did the database connection fail?
            {
                cerr << "Connection to database failed." << endl
                     << "Error returned: " << data.ErrorMessage() << endl;
                exit(1);
            }
         
            cout << "Enter a state code:  ";                    // prompt user for a state code
            cin.get(state_code, 3, '\n');
         
            sprintf(query_string,                               // create an SQL query string
                    "SELECT name \
                     FROM statename \
                     WHERE code = '%s'", state_code);
         
            if ( !data.ExecTuplesOk(query_string) )             // send the query
            {
                cerr << "SELECT query failed." << endl;
                exit(1);
            }
         
            for (int i=0; i < data.Tuples(); i++)               // loop through all rows returned
                    cout << data.GetValue(i,0) << endl;         // print the value returned
         
            return 0;
        }
         

LIBPQ++ allows database access using object methods rather than function calls.