byte and PHP

I´m about to do some web aplications that will save data in a postgreSQL
database, but I have one problem: I don´t understand the way postgreSQL saves
byte files.

I heard about bytea and Large Objects. Are they the same?

And how do I insert, say, pdf files in my database?

I looked for examples, but didn´t find much (in PHP, obviously).

Saludos... :-)

--
Porqué usar una base de datos relacional cualquiera,
si podés usar PostgreSQL?
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Martín Marqués                  |        mmarques@unl.edu.ar
Programador, Administrador, DBA |       Centro de Telematica
                       Universidad Nacional
                            del Litoral
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