Can someone explian to me the purpose of doing (Su - Oracle) while working in a Unix environment? I know that with System, Sys, and Internal you can perform a lot of administrative duties within Oracle but why SU - Oracle or the Unix id Oracle is so important. Thanks.
oracle is most likely an operating system user, while system and sys are database users. su oracle will log you into the oracle operating system user provided you know the password, so you can manage the database and related filesystems.