Relational databases provide a way to store information in a collection of tables and define links between them. The concept of a relational database has been around since the 70s, and since then they have become the prevailing database standard. A software package that manages relational databases is known as a Relational Database Management System, or RDBMS.
Relational databases are created, modified and queried using SQL, which stands for Structured Query Language. Although there are slight variations between the SQL syntax used by the various RDBMSs available today, SQL can be considered a common standard.
This guide takes a look at some of the more popular RDBMSs, provides tips on to create databases, and covers some of the issues surrounding database security.