Question

Firstly I add markers to the overlay:

private MapOverlay itemizedOverlay;

Cursor items = mDbHelper.fetchAllItems();
startManagingCursor(items);

for (int i = 0; i < items.getCount(); i++) {
    items.moveToPosition(i);
    OverlayItem overlayItem = new OverlayItem(markerPoint, "", "");
    itemizedOverlay.addOverlay(overlayItem);
}
mapOverlays.add(itemizedOverlay);

Now I need to update markers (change drawable).
Can I do:

Cursor items = mDbHelper.fetchAllItems();
startManagingCursor(items);

for (int i = 0; i < items.getCount(); i++) {
    items.moveToPosition(i);
    itemizedOverlay.getItem(i).setMarker();
}
mapOverlays.add(itemizedOverlay);

Will itemizedOverlay.getItem(i) always return items in the same sequence?
Records in the database are not added/deleted.

Answer 1

Will itemizedOverlay.getItem(i) always return items in the same sequence?

That is up to you. You are the one implementing getItem().