Overview

The repository of the Enterprise Manager is nothing more than a simple database. There is however two imporatnt requirements, the database should support:

Partitioning
Be Enterprise Edition

Since any Oracle Enterprise Edition database supports partitioning, you can install a simple database OR you can use Oracle predone configuration depending on the purpose of the Enterprise Manager:

Simple
Small
Medium
Large
Enterprise

Depending on your company needs, you can choose one of the predone templates for repository.