On Fri, 17 Jan 2020 at 06:14, Pengzhou Tang <pt...@pivotal.io> wrote: > > I am wondering whether a simple auto-updatable view can have a conditional > update instead rule.
Well, the decision reached in [1] was that we wouldn't allow that. We could decide to allow it now as a new feature enhancement, but it wouldn't be a back-patchable bug-fix, and to be honest I wouldn't be particularly excited about adding such a feature now. We already get enough reports related to multiple rule actions behaving in counter-intuitive ways that trip up users. I don't think we should be enhancing the rule system, but rather encouraging users not to use it and use triggers instead. > The document also says that: > "There is a catch if you try to use conditional rules for complex view > updates: there must be an unconditional > INSTEAD rule for each action you wish to allow on the view" which makes me > think a simple view can have a > conditional INSTEAD rule. And the document is explicitly changed in commit > a99c42f291421572aef2: > - There is a catch if you try to use conditional rules for view > + There is a catch if you try to use conditional rules for complex view > > Does that mean we should support conditional rules for a simple view? > No. I don't recall why that wording was changed in that commit, but I think it's meant to be read as "complex updates on views" -- i.e., the word "complex" refers to the complexity of the update logic, not the complexity of the view. Nothing in that paragraph is related to complex vs simple views, it's about complex sets of rules. Regards, Dean [1] https://www.postgresql.org/message-id/25777.1352325888%40sss.pgh.pa.us
