oracle中INDEX BY BINARY_INTEGER 的作用

创建一个集合类型的时候:一般都会在后面添加 INDEX BY BINARY_INTEGER

TYPE Type_Value IS TABLE OF varchar2(15) INDEX BY BINARY_INTEGER;

加了”index by binary_integer ”后,varchar2类型的下标就是自增长。就不需要每次都 extend 了。

 

没加“index by binary_integer”时:

declare
  type numbers is table of number;
  m numbers := numbers();
begin
  m.extend;
  m(1) := 2;
  m.extend;
  m(2) := 3;
  for i in1 .. m.count loop
      dbms_output.put_line(m(i));
  end loop;
end;

而如果加了“index by binary_integer”,代码如下写就可以达到上面的效果

declare 
    type numbers is table of number index by binary_integer;
    m numbers;
begin
    m(1) := 2;
    m(2) := 3;
    for i in 1..m.count loop
        dbms_output.put_line(m(i));
    end loop;
end;

 

posted @ 2021-01-07 11:14  masha2017  阅读(991)  评论(0编辑  收藏  举报