来自Odp.net中Oracle的多个结果集,没有refcursors

SELEct a,b,c from y;
select d,e,f from z;

begin 
  open :1 for SELEct count(*) from a; 
  open :2 for SELEct count(*) from b; 
end;

在Oracle中,引用游标是指向数据的指针,而不是数据本身.
因此,如果一个过程返回两个引用游标,则客户端仍然必须从这些游标中获取行(并引发网络命中).

因此,如果数据量很小,您可能希望调用只返回值的过程.
如果数据量很大(数千行),那么它无论如何也不会是单个网络旅行,因此当你在游标之间切换时,额外的一两个不会产生太大的影响.

另一种选择是单个选择返回所有行.这可能是一个简单的union all

SELEct a,c from y union all SELEct d,f from z;

它可以是流水线表功能

create or replace package test_pkg is
    type rec_two_cols is record
        (col_a  varchar2(100),col_b       varchar2(100));
    type tab_two_cols is table of rec_two_cols;
    function ret_two_cols return tab_two_cols pipelined;
end;
/

create or replace package body test_pkg is
    function ret_two_cols return tab_two_cols pipelined
    is
        cursor c_1 is SELEct 'type 1' col_a,object_name col_b from user_objects;
        cursor c_2 is SELEct 'type 2' col_a,object_name col_b from user_objects;
        r_two_cols  rec_two_cols;
    begin
        for c_rec in c_1 loop
            r_two_cols.col_a := c_rec.col_a;
            r_two_cols.col_b := c_rec.col_b;
            pipe row (r_two_cols);
        end loop;
        for c_rec in c_2 loop
            r_two_cols.col_a := c_rec.col_a;
            r_two_cols.col_b := c_rec.col_b;
            pipe row (r_two_cols);
        end loop;
        return;
    end;
end;
/
SELEct * FROM table(test_pkg.ret_two_cols);

我相信最新版本的ODP for 11g允许用户定义的类型可能有所帮助.