private InterpreterResult doInterpret(
CommonTree tree, ExecutionContext ctx) {
assertTokenType(tree, MqlParser.COMMAND);
// setup the query
DaoQuery query = new DaoQuery();
query.setDB(db);
query.setObjectMapper(objectMapper);
// set collection
query.setCollection(child(tree, 0).getText());
// read criteria
CommonTree actionTree = null;
if (child(tree, 1).getType()==MqlParser.CRITERIA) {
readCriteria(child(tree, 1), query, ctx);