QML Global Object

Database API

The openDatabaseSync() and related functions provide the ability to access local offline storage in an SQL database.

These databases are user-specific and QML-specific, but accessible to all QML applications. They are stored in the Databases subdirectory of QDeclarativeEngine::offlineStoragePath(), currently as SQLite databases.

The API can be used from JavaScript functions in your QML:

 import QtQuick 1.0

 Rectangle {
     color: "white"
     width: 200
     height: 100

     Text {
         text: "?"
         anchors.horizontalCenter: parent.horizontalCenter
         function findGreetings() {
             var db = openDatabaseSync("QDeclarativeExampleDB", "1.0", "The Example QML SQL!", 1000000);

             db.transaction(
                 function(tx) {
                     // Create the database if it doesn't already exist
                     tx.executeSql('CREATE TABLE IF NOT EXISTS Greeting(salutation TEXT, salutee TEXT)');

                     // Add (another) greeting row
                     tx.executeSql('INSERT INTO Greeting VALUES(?, ?)', [ 'hello', 'world' ]);

                     // Show all added greetings
                     var rs = tx.executeSql('SELECT * FROM Greeting');

                     var r = ""
                     for(var i = 0; i < rs.rows.length; i++) {
                         r += rs.rows.item(i).salutation + ", " + rs.rows.item(i).salutee + "\n"
                     }
                     text = r
                 }
             )
         }

         Component.onCompleted: findGreetings()
     }
 }

The API conforms to the Synchronous API of the HTML5 Web Database API, W3C Working Draft 29 October 2009.

The SQL Local Storage example demonstrates the basics of using the Offline Storage API.