This Object side of postgresql

Hello

I'm french ( you may already note it !)

I would like to have some light on the aspect Object of pgsql . When
we talk about about a object base , it's just because we can specify a
oid in a field or can we put directly a row of a table in a other table
?

If i make a table called table1 (with some field ) . I can create an
other table called table2 with a field who have the type table1 . Really
?
If it possible , what is the interest compared to a relationnal
approach : a field in table2 who contains a pointer (identifiant) on one
tuple of table1 ?

I'm sorry , if i haven't be really clear and i hope ,you'll be more
.

Thanks a lot

loic