小编ram*_*538的帖子

CREATE OR REPLACE TYPE ty_1 AS OBJECT ( fn VARCHAR2(100),
                                        sl NUMBER,
                                        hd DATE );
CREATE OR REPLACE TYPE ty_1_table AS TABLE OF ty_1;

CREATE OR REPLACE FUNCTION FN_RET_COL
  RETURN ty_1_table
AS
  c ty_1_table := TY_1_TABLE();
  BEGIN
    c.extend;
    C(1) := TY_1('A', 1, '10-JUN-2013');
    c.extend;
    C(2) := TY_1('B', 2, '11-JUN-2013');
    c.extend;
    C(3) := TY_1('C', 3, '12-JUN-2013');

    RETURN c;
  END;

CREATE OR REPLACE FUNCTION FN_RET_PIPE RETURN ty_1_table PIPELINED IS
  BEGIN
    PIPE ROW (TY_1('A', 1, '10-JUN-2013'));
    PIPE ROW (TY_1('B', 2, '11-JUN-2013'));
    PIPE ROW …

为什么在基于表的列创建函数时在user_tab_cols中创建条目？

 create table t1(a varchar2(100), b number);

 select * from user_tab_cols where table_name = 'T1'; -- Two rows coming

 create index idx1 on t1(upper(a));

 select * from user_tab_cols where table_name = 'T1'; -- Three rows coming

在user_tab_cols中输入条目的原因是什么？

物化视图中的强制刷新和完全刷新有什么区别

CREATE MATERIALIZED VIEW MV1 REFRESH FORCE ON DEMAND AS SELECT * FROM T1;
CREATE MATERIALIZED VIEW MV1 REFRESH COMPLETE ON DEMAND AS SELECT * FROM T1;
CREATE MATERIALIZED VIEW MV1 REFRESH ON DEMAND AS SELECT * FROM T1;

需要这些陈述之间的简短区别吗？