视图--bai
/*视图的必要性 create view population_all_view as select xxxx 详细信息 from qgck where rownum<500 -- sql语句不易读懂 create view population_all_view as select * from qgck where rownum<500;-- sql语句超出负载。 */ select * from scott.emp; --视图的创建 查询员工编号、员工名及所在部门的名称 create or replace view emp_basic_info_view as select scott.emp.empno as 员工编号,scott.emp.ename as 员工名, scott.dept.dname as 部门名 from scott.emp ,scott.dept where scott.emp.deptno = scott.dept.deptno --查询视图 select * from emp_basic_info_view delete from system.emp_basic_info_view where 员工编号='8000'; --练习1