Method reset

src/java/simpledb/index/BTreeScan.java:86–107

Reset the tableid, and tableAlias of this operator. @param tableid the table to scan. @param tableAlias the alias of this table (needed by the parser); the returned tupleDesc should have fields with name tableAlias.fieldName (note: this class is not respon

(int tableid, String tableAlias)

	 *            tableAlias.null, or null.null).
	 */
	public void reset(int tableid, String tableAlias) {
		this.isOpen=false;
		this.alias = tableAlias;
		this.tablename = Database.getCatalog().getTableName(tableid);
		if(ipred == null) {
			this.it = Database.getCatalog().getDatabaseFile(tableid).iterator(tid);
		}
		else {
			this.it = ((BTreeFile) Database.getCatalog().getDatabaseFile(tableid)).indexIterator(tid, ipred);
		}
		myTd = Database.getCatalog().getTupleDesc(tableid);
		String[] newNames = new String[myTd.numFields()];
		Type[] newTypes = new Type[myTd.numFields()];
		for (int i = 0; i < myTd.numFields(); i++) {
			String name = myTd.getFieldName(i);
			Type t = myTd.getFieldType(i);

			newNames[i] = tableAlias + "." + name;
			newTypes[i] = t;
		}
		myTd = new TupleDesc(newTypes, newNames);
	}

	public BTreeScan(TransactionId tid, int tableid, IndexPredicate ipred) {
		this(tid, tableid, Database.getCatalog().getTableName(tableid), ipred);