A DBMS that is based on a relational model is called a relational database management system. In this system, data is stored in tables. Each table represents only one entity and the columns of a table represent the properties of that entity. Also, each row contains a single record of that entity. In a relational model, two tables are related using the foreign key values. Relational databases support transaction systems, where each transaction must either happen or not happen at all. This is because of the ACID properties of relational databases.