DBMS_OUTPUT.PUT_LINE 不打印 [英] DBMS_OUTPUT.PUT_LINE not printing

问题描述

当执行下面的代码时，它只是说程序已经完成，并没有打印我想要的信息(名字，姓氏)，然后是下表中选择查询的其他值.

When executing the following code, it just says the procedure is completed and doesn't print the infomation i want it to (firstName, lastName) and then the other values from the select query in a table below.

 CREATE OR REPLACE PROCEDURE PRINT_ACTOR_QUOTES (id_actor char)
AS
CURSOR quote_recs IS
SELECT a.firstName,a.lastName, m.title, m.year, r.roleName ,q.quotechar from quote q, role r,   
rolequote rq, actor a, movie m
where
rq.quoteID = q.quoteID
AND
rq.roleID = r.roleID
 AND
r.actorID = a.actorID
AND
r.movieID = m.movieID
AND
 a.actorID = id_actor;
BEGIN
FOR row IN quote_recs LOOP
DBMS_OUTPUT.PUT_LINE('a.firstName' || 'a.lastName');

end loop;
END PRINT_ACTOR_QUOTES;
/ 

当设置服务器输出时，我得到

When setting server output on, I get

a.firstNamea.lastName
a.firstNamea.lastName
a.firstNamea.lastName
a.firstNamea.lastName

多次！

推荐答案

它只是说程序完成了"这句话中的它"是什么?

What is "it" in the statement "it just says the procedure is completed"?

默认情况下，大多数工具不会为 dbms_output 配置缓冲区来写入，也不会在代码执行后尝试从该缓冲区读取.另一方面，大多数工具都具有这样做的能力.在 SQL*Plus 中，您需要使用命令 set serveroutput on [size N|unlimited].所以你会做类似的事情

By default, most tools do not configure a buffer for dbms_output to write to and do not attempt to read from that buffer after code executes. Most tools, on the other hand, have the ability to do so. In SQL*Plus, you'd need to use the command set serveroutput on [size N|unlimited]. So you'd do something like

SQL> set serveroutput on size 30000;
SQL> exec print_actor_quotes( <<some value>> );

在 SQL Developer 中，您将转到 View |DBMS 输出 以启用 DBMS 输出窗口，然后按下绿色加号图标以启用特定会话的 DBMS 输出.

In SQL Developer, you'd go to View | DBMS Output to enable the DBMS Output window, then push the green plus icon to enable DBMS Output for a particular session.

此外，假设您不想为每一行打印文字a.firstNamea.lastName"，您可能想要

Additionally, assuming that you don't want to print the literal "a.firstNamea.lastName" for every row, you probably want

FOR row IN quote_recs
LOOP
  DBMS_OUTPUT.PUT_LINE( row.firstName || ' ' || row.lastName );
END LOOP;

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