Oracle OCI8 support for CI 4

Oracle is not supported for Database session.
You need to implement OCI8Handler.

Only MySQL and PostgreSQL databases are officially supported, due to lack of advisory locking mechanisms on other platforms. Using sessions without locks can cause all sorts of problems, especially with heavy usage of AJAX, and we will not support such cases. Use the close() method after you’ve done processing session data if you’re having performance issues.
https://codeigniter4.github.io/CodeIgnit...ler-driver