how to pass arguments to PhoneGap database transaction function

Question

I have a working PhoneGap database transaction where I am able to run a sql query and process the results. However, in an effort to make it reusable, I need to be abe to pass arguments to the querying function. There should a better way than declaring global variables and accessing them/resetting in the query function. Appreciate any help in converting this:

    //update images function
    function updateGalleryCovers() {
        var db = window.openDatabase("test db", "1.0", "Cordova DB", 200000);
        db.transaction(queryDB_u_g, errorCB);
    }
    //Query the database
    function queryDB_u_g(tx) {
        var query = 'SELECT cover_img, objectId FROM USER_GALLERY WHERE userId="'+getUserId()+'"';
        tx.executeSql(query, [], querySuccess_u_g, errorCB);
    }
//Query success callback
function querySuccess_u_g(tx, results) {
    var len = results.rows.length;
    for (var i=0; i<len; i++){
        // process results
    }
}

to something like this:

    //update images function
    function updateGalleryCovers(userid) {
        var db = window.openDatabase("test db", "1.0", "Cordova DB", 200000);
        db.transaction(queryDB_u_g, userid, errorCB);
    }
    //Query the database
    function queryDB_u_g(tx, userid) {
        var query = 'SELECT cover_img, objectId FROM USER_GALLERY WHERE userId="'+userid+'"';
        tx.executeSql(query, [], querySuccess_u_g, errorCB);
    }
//Query success callback
function querySuccess_u_g(tx, results) {
    var len = results.rows.length;
    for (var i=0; i<len; i++){
        // process results
    }
}

Thanks!

Answer 1

The transaction functions are offered by sqlite and not phonegap. Its true that you can't pass extra variables to the functions because of the method signature sqlite accepts.

But here's a work around for the same:

db_conn.transaction( function(tx){ your_function(tx, parameter1, parameter2) }, ErrorCallBack );

Here you are passing a dummy function to the transaction success callback and taking the transaction object along with it.

Hope that helps