Tables¶

Introduction¶

The foundation of relational databases is relational theory, and its basis is the Entity-Relationship Model (E-R). Simply put, it consists in representing a fragment of reality using entity relationships, i.e. data storage structures For relational databases, it will always be a set of tables in which information is aggregated. In addition, the tables will have specific connections between them:

ENTITY CLASS, RELATION (Model ER) <=> TABLE (RDBMS) <=> CLASS (object-oriented languages)

Table¶

According to the theory of relational databases, tables are the place where data is stored. In addition, the relationship itself is also a table. This structure consists of rows and columns. Each line describes one record (single information / data set). The column, on the other hand, is responsible for describing the properties / structure of a given record.

The above table is responsible for storing data about persons. This table consists of three columns:

• Name
• Surname
• Date of birth

The table has three records representing three independent information.