Relational Database Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. Relationships may be created and maintained across and among the data and tables. In a relational database, relationships between data items are expressed using tables.

Interdependencies among these tables are expressed by data values rather than by pointers. This allows for a high degree of data independence. An RDBMS can recombine the data items from different files, providing powerful tools for data usage.