I would think the rule qualification would tell the system not to run the rule in the event that it
does not meet the qualification. According to the docs:
What is a rule qualification? It is a restriction that tells when the actions of the rule
should be done and when not. This qualification can only reference the pseudorelations NEW and/or
OLD, which basically represent the relation that was given as object (but with a special meaning).
In the event that the qualification is met, the database only does the rule and not the insert, as
is directed by the Instead keyword and as I am expecting. However, in the event that the
qualification is not met then I would expect it to not do the rule as I understand it to say in the
docs.
Sim
Martijn van Oosterhout wrote:
On Tue, Mar 13, 2007 at 02:15:01PM +0200, Sim Zacks wrote:
select version()
"PostgreSQL 8.0.1 on i686-pc-linux-gnu, compiled by GCC
i686-pc-linux-gnu-gcc (GCC) 3.3.5 (Gentoo Linux 3.3.5-r1, ssp-3.3.2-3,
pie-8.7.7.1)"
I am sure that I must have missed something here because I read the
documentation and searched the forums and it all seems fairly
straightforward.
Rules don't work the way you think they do. They're sort of macro
expansions. What's ahppening when you insert is the rule splits it into
two statements, one insert and one update, with the where conditions
adjusted. Depending on the order I imagine that it could do both.
I don't think rules can do what you want. What you need in the SQL
MERGE command, but postgresql doesn't support that. A stored procedure
could do it.
Have a nice day,
