A Relational Database Management System (RDBMS) is based on the relational model, which was proposed by E. F. Codd.
The fundamental principle of the relational model is that all data is stored and represented in two-dimensional structures called relations.
In common parlance, these relations are known as tables.
Each table consists of rows (also called tuples or records) and columns (also called attributes or fields).
While data is ultimately stored in binary format on the disk, the logical structure and format in an RDBMS is the table.
Graph databases store data in graphs, and Object databases store data as objects.