Method open

src/java/simpledb/index/BTreeFile.java:1417–1429

Open this iterator by getting an iterator on the first leaf page applicable for the given predicate operation

()

	 * for the given predicate operation
	 */
	public void open() throws DbException, TransactionAbortedException {
		BTreeRootPtrPage rootPtr = (BTreeRootPtrPage) Database.getBufferPool().getPage(
				tid, BTreeRootPtrPage.getId(f.getId()), Permissions.READ_ONLY);
		BTreePageId root = rootPtr.getRootId();
		if(ipred.getOp() == Op.EQUALS || ipred.getOp() == Op.GREATER_THAN 
				|| ipred.getOp() == Op.GREATER_THAN_OR_EQ) {
			curp = f.findLeafPage(tid, root, ipred.getField());
		}
		else {
			curp = f.findLeafPage(tid, root, null);
		}
		it = curp.iterator();
	}

	/**
	 * Read the next tuple either from the current page if it has more tuples matching