Question

I am making a user management system using PyQT4 + PostgreSQL 9.1. While writing the following code for establishing connection with the database, i get syntax error :-

from PyQt4 import QtSql, QtGui , QtCore
import _sha256
import psycopg2


def createConnection(): 

    QSqlDatabase db = QSqlDatabase.addDatabase("QPSQL"); 
    db.setDatabaseName("mysite");
    db.setUserName("postgres");
    db.setPassword("password");
    db.setHostName("localhost");
    bool ok = db.open();
    if not db.open():
        QtGui.QMessageBox.critical(None, QtGui.qApp.tr("Cannot open database"),
                QtGui.qApp.tr("Unable to establish a database connection.\n"
                              "This example needs PostgreSQL support."),
                QtGui.QMessageBox.Cancel)
        return False

    query = QtSql.QSqlQuery()
    query.exec_("create table usermanagement(ID int primary key,"
                "userid int,firstname varchar(20), lastname varchar(20),usertype varchar(15),password varchar(20),)")
    query.exec_("insert into usermanagement values(1, 'Danny','Boyle','normaluser','normaluser')")

    return True

The error message is as follows:-

QSqlDatabase db = QSqlDatabase.addDatabase(“QPSQL”);
^
SyntaxError: invalid syntax

Answer 1

You can’t declare variable types in Python; a classname followed by a space followed by a variable name is not Python syntax.

Just do db = QSqlDatabase.addDatabase("QPSQL").

(You have the same problem at bool ok = ...)

Your code also doesn’t define QSqlDatabase anywhere to begin with; presumably you mean to import it from somewhere.

Also remove all of the semicolons from your code; they’re not required as statement terminators in Python and are considered bad style.