Sam Mason wrote:
On Fri, Jan 30, 2009 at 02:47:49PM -0500, Merlin Moncure wrote:
On 1/30/09, Tom Lane <t...@sss.pgh.pa.us> wrote:
Merlin Moncure <mmonc...@gmail.com> writes:
> You are missing the point, using the composite type allows you to
> build the insert without knowing the specific layout of the
> table...
Surely at *some* level you have to know that.
You don't (if I understand your meaning) ...you just have to make sure
the destination of the insert is the same as the source.
Sounds as though there are at least two levels that know the specific
layout of the tables involved then. 1) PG has to know the structure of
the tables, and 2) you application relies on the fact that tables of the
What merlin is trying to solve is home-grown replication. By
definition, the master and slave must have the same table(s). So I
think he is looking for a more elegant method of performing slave
updates; rather than mirror.field_a=master.field_a,
mirror.field_b=master.field_b, etc... until you are blue in the face.
What makes single field updating even worse is the maintained overhead
involved if the table structure changes; can't just alter the two
tables, you also have to modify the UPDATE statement.
> same name have the same structure. Sounds like a very simple ah-hoc
> nominal type system to me.
No. Its an ad-hoc replication system. A change to UPDATE is needed for
it to work, not a type system.
--
Andrew Chernow
eSilo, LLC
every bit counts
http://www.esilo.com/
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