Comments on: Truncate Partition

By: kshashikanth seo (@kshashikanthseo)

kshashikanth seo (@kshashikanthseo) — Tue, 19 Jun 2012 03:47:59 +0000

Nice Article,
I had also written an Article about Disabling and Enabling Constraints, What precautions to be taken while performing these Operations etc.. in http://www.way2db.in/oracle-constraints.html

By: Jonathan Lewis

Jonathan Lewis — Thu, 07 Jun 2012 18:04:42 +0000

Mohamed,

Thanks for that – I really ought to read my own work from time to time ;)

Interestingly one of the notes I wrote on that blog item claimed that the mechanism described by George Eadon doesn’t work with one particular pattern. However I can’t find the test case to justify the claim, and the quick test I ran based on the description didn’t repeat the problem in 11.1.0.7 or 11.2.0.3, so either there was a limitation in the earliest version that has been addressed, or I was wrong.

By: Jonathan Lewis

Jonathan Lewis — Thu, 07 Jun 2012 17:47:12 +0000

George,

Thanks for highlighting that possibility. The OP was talking about 10g so the option made available through 11g completely slipped my mind.

By: Houri Mohamed

Houri Mohamed — Wed, 06 Jun 2012 13:37:24 +0000

Jonathan

You’ve blogged about such a smilar case several years ago

http://jonathanlewis.wordpress.com/2006/12/10/drop-parent-partition/

Best regards

By: lkafle

lkafle — Wed, 06 Jun 2012 02:47:41 +0000

Reblogged this on lava kafle kathmandu nepal.

By: George Eadon

George Eadon — Tue, 05 Jun 2012 17:48:44 +0000

In this example the child table could be PARTITION BY REFERENCE(c_fk_p) and then TRUNCATE PARTITION in the parent will be allowed when the corresponding partition in the child is empty.

In general, PARTITION BY REFERENCE is useful if you have tables connected by a referential constraint and you want to equi-partition the child and parent tables. Partition maintenance operations such as ADD, DROP, SPLIT and MERGE PARTITION will cascade implicitly to the child when performed on the parent. Since the rdbms is enforcing equi-partitioning, the enabled ref constraint does not block operations such as TRUNCATE and EXCHANGE PARTITION when the relevant partition of the other table is empty.