CREATE OR REPLACE PROCEDURE schema_name.CHECKS
IS
   tbl_name        VARCHAR2 (50);
   constraint_nm   VARCHAR2 (100);
   CURSOR cur_constraint
   IS
      SELECT DISTINCT table_name,constraint_name
        FROM all_constraints
       WHERE     constraint_type = 'R'
             AND STATUS = 'ENABLED'
             AND R_OWNER = 'owner1'
             AND r_constraint_name = 'constraint1';
BEGIN
   DBMS_OUTPUT.put_line ('Constraint Name');
   OPEN cur_constraint;
   LOOP
      FETCH cur_constraint
      INTO tbl_name,constraint_nm;
      EXIT WHEN cur_constraint%NOTFOUND;
      DBMS_OUTPUT.put_line (constraint_nm||'~~'||tbl_name);
   END LOOP;
   close cur_constraint;
END CHECKS;

我执行此过程

set serveroutput on
 
BEGIN
   schema_name.CHECKS ();
END;

我得到的输出是

Procedure created.
Constraint Name
PL/sql procedure successfully completed.

它没有返回任何结果,但理想情况下它应该返回一行(用于定义游标的select查询将返回一行).

当我像这样执行上面的代码作为PL / sql块时

DECLARE
   tbl_name        VARCHAR2 (50);
   constraint_nm   VARCHAR2 (100);
   CURSOR cur_constraint
   IS
      SELECT DISTINCT table_name,constraint_name
        FROM all_constraints
       WHERE     constraint_type = 'R'
             AND STATUS = 'ENABLED'
             AND R_OWNER = 'owner1'
             AND r_constraint_name = 'constraint1';
BEGIN
   FOR i IN cur_constraint
   LOOP
      EXIT WHEN cur_constraint%NOTFOUND;
      DBMS_OUTPUT.put_line (i.constraint_name||' is in '||i.table_name);
   END LOOP;
END;

它按预期返回一行.

请帮助我理解为什么当逻辑相同时它会表现得很奇怪,除了我执行它的方式.