Marc Herbert wrote:
> What would you recommend to unambiguously identify a Blob column in a
> arbitrary ResultSet, using only JDBC?
I don't think there is any way to do this in general, via JDBC or any
other interface; you need schema-specific knowledge to work out which
oid columns refer to LOs and which refer to a different sort of oid
somewhere else.
The actual LO interface itself just looks like "create LO" -> "ok,
here's an oid identifying it"; there's nothing that ties the column you
happen to use to store that oid to the LO itself. See
http://www.postgresql.org/docs/8.0/static/largeobjects.html for more
details.
For comparison, contrib/vacuumlo assumes that any (non-system-generated)
oid column in the system could potentially reference a LO (in GC-speak
it's a conservative collector).
> PS: why do LOBs seem to use regular oids instead of some other less
> ambiguous say, "loid" ?
It's just an artifact of the implementation AFAIK.
-O