Question

function GetMe(id) {

DB.transaction(
    function (transaction) {

        transaction.executeSql("SELECT * FROM users WHERE id = ?", [id], function (transaction, results) {

            if(results.rows.length > 0) {

                var row = results.rows.item(0);

                return row.name;


            }

        }, errorHandler);
    }
);

}

alert(GetMe(1)); // id 5 exists in users table and alert shows empty

the above code dosent work so i tried the below codes

function GetMe(id) {

var retval;

DB.transaction(
    function (transaction) {

        transaction.executeSql("SELECT * FROM users WHERE id = ?", [id], function (transaction, results) {

            if(results.rows.length > 0) {

                var row = results.rows.item(0);

                retval = row.name;
                //alert('IN ' + retval); //works

            }

        }, errorHandler);
    }
);

//alert('OUT ' + retval); // undefined

return retval;  // undefined

}

alert(GetMe(1));  // undefined

the above code should work fine but it dosent i dont know whats wrong with it , i tried almost everything

can someone tell me whats wrong and help me fix this thanks 🙂

Answer 1

This looks like it’s because DB.transaction is asynchronous. What you’ll need to do is pass in a callback function to your GetMe() function, e.g.

GetMe(1, function (data) {

});

And then modify GetMe as follows:

function GetMe(id, callback) {
    DB.transaction(function (transaction) {
        transaction.executeSql("SELECT * FROM users WHERE id = ?", [id], function (transaction, results) {
            if(results.rows.length > 0) {
                var row = results.rows.item(0);
                callback.call(null, row.name);
            }
        }, errorHandler);
    });
}