Relational Database - Definition

A relational database is a software system which holds data in fields in a set of tables which are linked together.

That’s it! Well almost … Its not really a relational database unless the fields, tables and links are designed intelligently. By creating an appropriate structure for the data, we ease the process of designing forms and reports to allow users to interact with the data.

A lot of thought has to go into what data is required, how it is arranged in tables, and how those tables should be linked together. If we consider our database for owl sitings, we first need to consider what kinds of objects we want to hold information about. At the minimum we might need.

  • Types of Owl
  • Places
  • People who report sitings
  • Actual sitings

You would devise a table for each of these then decide on what fields you need in each table, i.e what information you want to hold about each of these items which are known as entities.

Then you would decide how to link the tables together. Each siting will be for a particular type of owl, in a particular place, by a particular person. The tables and fields article shows how two tables are linked together. The following diagram is called an entity relationship diagram.

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  • Scott Levy

    Thanks for the post. Here’s a tutorial that shows how you can easily build an online database-driven web application with a parent-child table relationship, without coding