Re: driver fails to handle strings in query statements properly

I tried it on a table which id was an int

Using "select 'id' as xxx from ..." Returns xxx as an unknown type
Using "select id as xxx from... " returns xxx as an int

I have no idea how the backend handles this, but if it can figure it out
in one instance why can't it figure it out when I put single quotes
around it?

Dave

-----Original Message-----
From: pgsql-jdbc-owner(at)postgresql(dot)org
[mailto:pgsql-jdbc-owner(at)postgresql(dot)org] On Behalf Of Tom Lane
Sent: October 2, 2001 5:19 PM
To: Barry Lind
Cc: Dave(at)micro-automation(dot)net; pgsql-jdbc(at)postgresql(dot)org
Subject: Re: [JDBC] driver fails to handle strings in query statements
properly

Barry Lind <barry(at)xythos(dot)com> writes:
> My thoughts as well. If we encounter an 'unknown' type, just return
> it
> as a String. Do you have time to fix this?

>> I suppose we could return it as a string when we are in doubt? Is
>> this reasonable since there are many other types it should be
>> returned as?

The backend will presently default to treating 'unknown' as type 'text'
if it hasn't got any better idea what to do, so I think it's reasonable
for JDBC to do likewise.

I believe the only case in which you could see 'unknown' reported as a
query result type is if a string literal is SELECTed without any
processing being done on it, viz

SELECT 'foo'

As soon as the literal is passed to a function or operator, sorted,
grouped, etc, the system will insist on resolving it to a non-unknown
type. If the usage context doesn't provide any other hint, 'text' will
be the chosen type.

regards, tom lane

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