// The bulk operation will return null to indicate that the database
// does not support the request bulk delete operation; in
// this case, we need to perform the query in-memory and
// manually delete the instances
if (!isUpdate)
sql[i] = dict.toDelete(mappings[i], sel, params);
else
sql[i] = dict.toUpdate(mappings[i], sel, _store, params,
updates);
if (sql[i] == null)