postgres blobs and PHP

I know I bothered with this, but I just don't get it.
Lets say I have a test table like this in a certain database:

CREATE TABLE test (
id_test SERIAL,
blob_text oid
);

Now I want to insert a good chunk of text in the blob_text field with PHP.
PHP has some postgres functions like pg_locreate, pg_lowrite, pg_loread, etc,
but it never specifies the table and it doesn't specify the field in the
table.
Now how does php know where to write the chunk of text (or the image, or
whatever)?
Can someone give me a hand?

TIA.

--
"And I'm happy, because you make me feel good, about me." - Melvin Udall
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Martín Marqués email: martin(at)math(dot)unl(dot)edu(dot)ar
Santa Fe - Argentina http://math.unl.edu.ar/~martin/
Administrador de sistemas en math.unl.edu.ar
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