Relational databases

This article presents the basis of the relational model. This model is currently the most used in order to describe computer databases regardless of the implemented applications. Due to its universal mathematical base (set theory) and its simplicity, the relational model has allowed for the emergence of non-algorithmic languages (SQL, QBE) in order to search for data in a base. This article firstly presents the data structuring process (normalization) and then proceeds to studying the operations which allow for the extraction of data from the base by means of requests. The article finally presents the interaction mechanisms of a program written in JAVA language with the data.