Hi folks,Please find attached a patch that implements SQL92-compatible updatable views. The patch introduces new semantics into the rule system: implicit and explicit rules. Implicit rules are created to implement updatable views:
_INSERT _NOTHING_INSERT (unconditional DO INSTEAD NOTHING rule) _DELETE _NOTHING_DELETE (unconditional DO INSTEAD NOTHING rule) _UPDATE _NOTHING_UPDATE (unconditional DO INSTEAD NOTHING rule)These rules are marked 'implicit' in pg_rewrite, the rewriter is teached to handle them different, depending on wether they are created with a rule condition (a view's CHECK OPTION) or not. The CHECK OPTION itself is implemented with a new system function and a conditional rule that evaluates the view's WHERE condition (pg_view_update_error()).
The supported syntax is CREATE VIEW foo AS SELECT ... [WITH [LOCAL | CASCADED] CHECK OPTION];The LOCAL and CASCADED keywords are optional when a CHECK OPTION is specified, the default is CASCADED (this syntax creates a shift/reduce conflict in the grammar file i don't know how to fix).
If a user wants his own rules with CREATE RULE to be created, the implicit rule gets dropped, depending what action the user selects.
The patch introduces support for pg_dump as well.Please note that the patch isn't complete yet, but it seems it's necessary to discuss its implementation on -hackers now.
Bernd
pgsql-view_update_8.2dev.tar.bz2
Description: Binary data
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