Oracle DB allows writing procedures in the language PL/SQL. These procedures are compiled and stored in database, and are executed within the same server process as the database, thus removing overhead related to transferring query results between processes or over the network.
PostgreSQL also has such a language, called PL/pgSQL. However, PostgreSQL also allows using a user-defined Procedural Language by writing a so-called Procedural Language Handler.
My question is: does Oracle DB allow using a user-defined Procedural Language?
I tried searching the web for "oracle" "Procedural Language Handler" but saw no relevant results.