Method fetchNext

src/java/simpledb/execution/Project.java:72–82

Operator.fetchNext implementation. Iterates over tuples from the child operator, projecting out the fields from the tuple @return The next tuple, or null if there are no more tuples

()

     * @return The next tuple, or null if there are no more tuples
     */
    protected Tuple fetchNext() throws NoSuchElementException,
            TransactionAbortedException, DbException {
        if (!child.hasNext()) return null;
        Tuple t = child.next();
        Tuple newTuple = new Tuple(td);
        newTuple.setRecordId(t.getRecordId());
        for (int i = 0; i < td.numFields(); i++) {
            newTuple.setField(i, t.getField(outFieldIds.get(i)));
        }
        return newTuple;
    }

    @Override
    public OpIterator[] getChildren() {