Introduction to Relational Databases: Tables, Relationships, Data Types, and SQL

It is Sunday, so I’m just going to do a simple introduction to a topic. Today’s topic is relational databases.

A relational database allows you to break data into logical, manageable units for easier maintenance and optimal database performance.
These units are tables, which consist of rows and columns. The relationships between tables are identified through a common key known as a primary key. Using common keys and fields, you can join multiple tables to form a large set of data.

A simple example of a database is a phone book. It has fields in a table such as names, addresses, and phone numbers. As people move, data must be maintained. You must update, add, and delete entries. People must be able to read the data.

The values (data) stored in the database are assigned data types. Data types provide rules for how values are stored, for example, length or whether the value is alphanumeric or a number. This eliminates data entry errors. For example, if the phone number field is defined as numeric only, letters cannot be added to the field.

One way to communicate with a relational database is with SQL (Structured Query Language).

There is much more to be said on this, but for those new to this, I hope you enjoyed this brief intro.

Enjoy the rest of your weekend!

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