Ahm, yup, PHP is not a database engine, but it offers some functions that is use to run PostgreSQL codes, such as pg_query, pg_connect, pg_copy_from, etc.
I think the function, pg_query() is 1 of the solutions that can be use in the creating a Oracle's Cursor-like in PHP. I'm not sure, but, the pg_query() returns a result set base from the pgsql code that is being passed to it. So maybe the returned result set of pg_query() can be use as a cursor.