Oracle:在迁移期间规范化数据
我有一个包含大量重复数据的表,我想将其重构为3个表 目前的结构如下:Oracle:在迁移期间规范化数据,oracle,normalization,data-migration,Oracle,Normalization,Data Migration,我有一个包含大量重复数据的表,我想将其重构为3个表 目前的结构如下: meeting_desc meeting_date topic_desc ... meeting1,2/3/2009,abc meeting1,2/3/2009,efg meeting1,2/3/2009,xyz meeting2,4/5/2009,aaa meeting2,4/5/2009,bbb 当前_表中的数据如下所示: meeting_desc meeting_date topic_desc ... meetin
meeting_desc
meeting_date
topic_desc
...
meeting1,2/3/2009,abc
meeting1,2/3/2009,efg
meeting1,2/3/2009,xyz
meeting2,4/5/2009,aaa
meeting2,4/5/2009,bbb
当前_表中的数据如下所示:
meeting_desc
meeting_date
topic_desc
...
meeting1,2/3/2009,abc
meeting1,2/3/2009,efg
meeting1,2/3/2009,xyz
meeting2,4/5/2009,aaa
meeting2,4/5/2009,bbb
我想创建一个会议表和一个主题表,其中PKs来自一个序列:
MEETING:
id
meeting_desc
meeting_date
TOPIC:
id
meeting_id
topic_desc
我搞不懂的是如何将数据插入到新表中。我试过:
insert into MEETING select distinct
seq.nextval, meeting_desc, meeting_date from current_table
但这当然行不通。有没有一种简单的方法来规范化数据?放置在子查询中的
不同的应该可以工作:
SQL> INSERT INTO meeting
2 SELECT seq.nextval, meeting_desc, meeting_date
3 FROM (SELECT DISTINCT meeting_desc, meeting_date
4 FROM current_table);
2 rows inserted
完成此操作后,您可以将新创建的表与旧表联接,以将生成的ID与子表关联:
SQL> INSERT INTO topic
2 SELECT m.id, topic_seq.NEXTVAL, ct.topic_desc
3 FROM current_table ct
4 JOIN meeting m ON (ct.meeting_desc = m.meeting_desc
5 AND ct.meeting_date = m.meeting_date);
5 rows inserted