The short and silly answer is that a remote database administrator (DBA) manages databases remotely. The longer answer is that a database manager is the party responsible for the installation of a company's database. In order to do this, the manager must evaluate the features of various database-related products and secure the ones judged most beneficial for the company.
Once underway, the DBA continues to oversee the development of the database to ensure it functions optimally. This includes close monitoring and tuning of the database, maintaining the documentation, planning for growth and responsibility for assigning user roles and privileges and looking after security concerns.
This...