Question

我的记录结构如下：

A - ＆GT;乙 - ＆GT; d - ＆GT;的F - ＆GT克

A - ＆GT; C - ＆GT;ü - ＆GT; W

乙 - ＆GT; X - ＆GT; Y

记录的关系只能与一个记录相关联，而不是一个记录只能有一个记录。在上述结构记录中，A＆＃39;是主记录。该表存储数据如下：

A - ＆GT;乙

乙 - ＆GT; d

d - ＆GT;˚F

的F - ＆GT克

A - ＆以及c

所以.......

如果我提供＆＃39; A＆＃39;对于PL / SQL过程，它应该返回所有级别与之关联的所有子记录。我想只有递归循环才能解决这个问题？请给我一个解决方案.. !!

提前致谢

Answer 1

您可以使用递归查询来实现目标：

WITH t AS (
              SELECT 'A' AS m, 'B' AS c FROM dual
    UNION ALL SELECT 'B' AS m, 'D' AS c FROM dual
    UNION ALL SELECT 'D' AS m, 'F' AS c FROM dual
    UNION ALL SELECT 'F' AS m, 'G' AS c FROM dual
    UNION ALL SELECT 'A' AS m, 'C' AS c FROM dual
    UNION ALL SELECT 'C' AS m, 'U' AS c FROM dual
    UNION ALL SELECT 'U' AS m, 'W' AS c FROM dual
    UNION ALL SELECT 'B' AS m, 'X' AS c FROM dual
    UNION ALL SELECT 'X' AS m, 'Y' AS c FROM dual
)
SELECT CONNECT_BY_ROOT(t.m) || sys_connect_by_path(c, ', ') AS list
FROM t
WHERE CONNECT_BY_ROOT(t.m) = 'A'
  AND NOT EXISTS (SELECT * FROM t t2 WHERE t2.m = t.c)
CONNECT BY NOCYCLE PRIOR c = m;

以上查询返回此结果：

A, B, D, F, G
A, B, X, Y
A, C, U, W

Answer 2

CREATE OR REPLACE PROCEDURE FIND_CHILD_RECORD (IN_MASTER_RECORD IN NUMBER)
IS
    V_CHILD_RECORD_LIST   NUMBER_LIST;   -- create a number type colletion list
BEGIN
   -- get all child record for the given master record
 SELECT CHILD_RECORD
 BULK COLLECT INTO V_CHILD_RECORD_LIST
 FROM RELATED_TABLE
WHERE MASTER_RECORD_NUMBER = IN_MASTER_RECORD; -- logic holds good only if one master record is present for one child.

--       iterate over all child records
FOR IDX IN 1 .. V_CHILD_RECORD_LIST.COUNT
LOOP
  -- create a global temp table to store child records
  INSERT INTO TT_CHILD_RECORDS
       VALUES (V_CHILD_RECORD_LIST (IDX));

  COMMIT;
  --call the same procedure recursively
  FIND_CHILD_RECORD (V_CHILD_RECORD_LIST (IDX));
END LOOP;
END;

--TT_CHILD_RECORDS table will hold all child records for a give master.

我用递归循环编写了上面的代码来查找所有子记录。这对我有用。如果我错了，请纠正我.. :)

如何在plsql中查找给出父记录的所有子记录？

2 个答案: