orale培训教材包括了所有的sql说明和实例

				delete from plsql101_purchase;
				
				insert into plsql101_purchase values('豆腐','张',to_date('2002/01/01','yyyy/mm/dd'),10);
				insert into plsql101_purchase values('钢笔','张',to_date('2002/02/01','yyyy/mm/dd'),10);
				insert into plsql101_purchase values('钢笔','关',to_date('2002/03/01','yyyy/mm/dd'),10);
				insert into plsql101_purchase values('钢笔','关',to_date('2002/04/01','yyyy/mm/dd'),10);