[Qt-qml] I am trying to use the aggregate SQL functions using SQLite in Javascript, called from QML and running under QtCreator (on a Mac)

[bruce.cichowlas at nokia.com]

Hi!

I am using QML with a database, a bit like the "samegame" example.

I think I have things set up pretty well, because I am able to perform queries like this without a problem:


     var query = 'SELECT * FROM ' + table + ' WHERE myfield >= ' + n1
        + ' AND myfield < ' + n2 + ' ORDER BY myfield desc';
     db.transaction(function(tx) {
         var rs = tx.executeSql(query);
         ret = rs;
         console.log(ret);
     });
     console.log("...return count: " + ret.rows.length);

However, I'm trying to figure out how to perform the SQL aggregate functions.  I haven't found any examples like this on a website.  For instance, following an SQLite example I found here 
http://developer.apple.com/library/safari/#documentation/iphone/conceptual/safarijsdatabaseguide/usingthejavascriptdatabase/usingthejavascriptdatabase.html

I wrote:

function showDocCount(db, table) {
  var result = "uninitialized";
  db.readTransaction(function (t) {
    t.executeSql('SELECT COUNT(*) AS c FROM ' + table, [], function (t, r) {
        console.log("*A*");
      result = r.rows[0].c;
    }, function (t, e) {
      // couldn't read database
    console.log("*B*");
      result = '(unknown: ' + e.message + ')';
    });
    console.log("*C*");
  });
  console.log("*D*");
  return result;
}

function getRecordCount(table){
    var db = openDatabaseSync("MyDB", "1.0", "Local Table", 100);
    return showDocCount(db, table);
}

...
console.log(getRecordCount('mytablename');

I expected to get back *A* and a record count, or maybe *B* and an SQL error.

Instead I got back:

*C*
*D*
uninitialized

which makes it appear that neither the successful nor the failure function were called.

Maybe I'm missing something easy.  In any event, it would be useful to see what a successful usage of something like    SELECT COUNT(*) ...  or  SELECT AVG(*)

Thanks,
Bruce