This project includes the implementation and assessment of database administration (DBA) activities of a retailer company on an Oracle Database environment that runs on a virtual machine (VM). The company stores important business information concerning customers, products and orders in a schema structure which is designed and owned by the user oe. Being a new DBA, the main role is to make sure that the database is secure, efficient, scalable, and according to the organisational access-control needs. The report is being done with special regards to the execution of core DBA functions, like tablespace management, user and profile creation, role-based access control, and data definition business, in terms of the given Entity Relationship Diagram (ERD) and business rules. Special focus is made on implementation of security policies by providing various degrees of access to the employees of different departments like Customer Service and Sales, according to their job duties. Besides the technical implementation, the report presents the specifications of design choices, and reasons behind them, considering potential options, and mentions constraints. Widespread oracle database errors have been investigated and the corresponding causes and solutions have been discussed to portray real-life problem-solving skills that are necessary to be considered successful in administering a database.