Tom Lane wrote:
Sam Mason <sam@xxxxxxxxxxxxx> writes:
I don't really know 8.4, but I believe you're saying here that you
explicitly want the values to be of basic INTERVAL type here, i.e. not
INTERVAL DAY TO HOUR for parameter 3.
Right, you can get the equivalent behavior from psql thus:
regression=# select '-12345'::interval::interval year;
interval
----------
00:00:00
(1 row)
regression=# select '12 11'::interval::interval year;
ERROR: invalid input syntax for type interval: "12 11"
LINE 1: select '12 11'::interval::interval year;
^
There is not any way to bind a more specific type to a parameter at the
protocol level.
I think PG may do the right thing if you
don't specify the types when preparing the query, but haven't tested.
Yeah, that should work (though I haven't verified it either). Another
common trick is to specify the type in the text of the query by casting
the parameter symbol:
PQprepare( ... $2::INTERVAL YEAR ... );
I'd say this is better style than hard-wiring numeric type OIDs into
your code.
Remember we are implementing a database driver with equivalent features
and an ODBC driver for PostgreSQL, executing queries with ? parameter
placeholders in the SQL text...
Since SQL Parameter types are not known at (4gl language-level) PREPARE
time, we wait for the (4gl) EXECUTE time to do the real PQprepare() with
paramTypes[]... (this is a pity by the way since we can't get any SQL
error at PREPARE time).
It's not that easy for us to add the ::<type> clauses because the conversion
of the ? placeholders to $n is done at PREPARE time, when types are not yet
yet... so this means major rewriting...
But this is all internal stuff you are not interested in, the main question
I would like to ask is:
What versions of PostgreSQL are 100% sure supporting the $n::<type> clauses?
We have to support all PostgreSQL versions, starting from 8.0 ...
Thanks
Seb
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