Using variables in SQLite queries

[gabor53]

Hi,
I have a qml file (MyComboBox.qml) which includes the ComboBox I want to reuse.
MyComboBox.qml:

import QtQuick 2.0
import QtQuick.Controls 2.1

Item {
    Rectangle {
        id: test
        width: 400
        height: 240
        color: "#d9d9ec"
        border.color: "blue"
        border.width: 2
        anchors.top: parent.top
        anchors.topMargin: 200
        anchors.centerIn: parent.Center

        ComboBox {

            //            model: ["doll", "duck", "owl"]
            anchors.horizontalCenter: parent.horizontalCenter
            anchors.top: parent.bottom
            anchors.topMargin: 30
            font.pixelSize: 22
            editable: true
            textRole: "what"
            height: 50
            width: 230
            background: Rectangle {
                color: "lightgreen"
                border.width: 2
                border.color: "darkgreen"
                radius: 25
            }
        }

        Component.onCompleted: {

            var db = JS.dbGetHandle()
            db.transaction(function (tx) {
                var results = tx.executeSql(
                            'SELECT "field" FROM "table" order by "field" desc')
                for (var i = 0; i < results.rows.length; i++) {
                    listModel.append({
                                         what: results.rows.item(i).what,
                                         checked: ""
                                     })
                }
            })
        }
    }
}
``
My main.qml, in which I want to use the ComboBox defined in MyComboBox, has the following code:

import QtQuick 2.9
import QtQuick 2.2
import QtQuick 2.0
import VPlayApps 1.0
import QtQuick.Controls.Styles 1.4

import QtQuick.Dialogs 1.3
import QtQuick.Controls 1.1
import QtQuick.Controls 1.4
import QtQuick.Controls 2.2
import QtQuick.Layouts 1.3
import QtQuick.LocalStorage 2.0
import QtQml.Models 2.3
import "Database.js" as JS

App {
MyComboBox {
var field = what
var table = dropboxWhatIs

    id: whatCombo
}

}
``

The Database.js has the following:

function dbUpdate2(table, field, newText) {
    var db = dbGetHandle()
    db.transaction(function (tx) {
        tx.executeSql('UPDATE "table" "field" = ?', ['newText'])
    })
}
``
My idea was to create one combobox and reuse it for displaying choices from several tables. To do that I have to define variables field, table and newTect in the main.qml. 
This code generates the JaaScript declaration is outside the Script element error for main.qml. Which is the best way to do what I am trying to do?
Thank you for your help.