oracle 在删除语句中使用 rowid
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Using rowid in a delete statement
提问by Revious
Is there any SEVERE contraindications to delete using rowid?
使用 rowid 删除是否有任何严重的禁忌症？
DELETE FROM NETATEMP.SFAC_TESTATA_CASISTICHE
WHERE ROWID IN ( SELECT MIN (ROWID)
FROM NETATEMP.SFAC_TESTATA_CASISTICHE
GROUP BY ID_CASO,
DESCRIZIONE_TECNICA,
DESCRIZIONE_ANALISI,
PDF,
SCARTI,
DATA_INIZIO_ANALISI,
DATA_FINE_ANALISI,
DATA_INSTRADAMENTO,
DATA_RISOLUZIONE,
STRINGA_RICERCA,
SETTIMANA,
DATA_INIZIO_SETT,
DATA_FINE_SETT,
FATTURAZIONE,
IN_ELABORAZIONE
HAVING COUNT (1) > 1);
回答by a_horse_with_no_name
If you assume that min(rowid)returns the "earliest" row, then yes, you have a problem (because it won't)
如果您假设min(rowid)返回“最早”行，那么是的，您有问题（因为它不会）
If you use min(rowid)only to get one of the duplicates (and you don't care which), then no, there is nothing wrong with that statement.
如果您min(rowid)仅用于获取其中一个副本（并且您不在乎哪个），那么不，该语句没有任何问题。
回答by tbone
A few things to be aware of. It seems you are depending on the rowid to give you the earliest row for your particular grouping (select min(rowid) ...). This won't always be true. The only way to guarantee you are deleting the earliest record is to use some column (like timestamp) that you can order by. Tom Kyte explains thisbetter than I could.
需要注意的几件事。似乎您依赖 rowid 为您的特定分组提供最早的行（选择 min(rowid) ...）。这并不总是正确的。保证您删除最早记录的唯一方法是使用您可以订购的某些列（如时间戳）。 Tom Kyte比我更好地解释了这一点。
A rowid implies NOTHING other than the location of the row physically. It does not imply age, order of insertion, or anything like that.
rowid 除了物理上的行位置外，没有任何其他含义。它并不意味着年龄、插入顺序或类似的东西。
Also, depending on the size of the table, you will generate a lot of redo/undo, and it may be beneficial in large tables to use pl/sql to delete in chunks and commit every x rows.
另外，根据表的大小，你会产生大量的redo/undo，在大表中使用pl/sql分块删除并每x行提交可能会有好处。
Just my thoughts
只是我的想法
