Could not open the PostgreSQL database in Qt -

could not open postgresql database qt.

    qdebug()<<qsqldatabase::drivers()      qsqldatabase_database=qsqldatabase::adddatabase("qpsql");     qsqldatabase_database.setdatabasename("myapp");     qsqldatabase_database.sethostname("localhost");     qsqldatabase_database.setport(5432);     qsqldatabase_database.setusername("postgres");     qsqldatabase_database.setpassword("1");      if(!qsqldatabase_database.open())     {       qdebug()<<"could not open database";       qdebug()<<qsqldatabase_database.lasterror().text();     }     else     {       qdebug()<<connected;     } 

output:

"qpsql,qpsql7" "could not open database" "driver not loaded driver not loaded" 

it windows 7 64 bit pc.

in pc qt not installed.

but in qt(qt 5.4) installed pc(windows 7 32 bit)  working perfectly!