請問有關Oracle(編號：6304)

請問Oracle各版本的功能主要為何,初學者應從何下手
Oracle Designer R2.1.2
Oracle Designer R2.1.2 Preconfigured RepoitoryPersonal Oracle Lite V2.4.3.1.1
Oracle Designer CASE Dictionary 5.1 Upgrade
Oracle Developer 2000 R.2.1
Oracle 8 Client V8.0.5.00
Programer 2000