What is a Database? And a DBMS?

A database is a collection of information carefully organized into a system.

The software on a computer that lets us organize data and represent the information an app needs is called a Database Management System, or DBMS.

A DBMS wraps the data in one place. It gives you a central way to store it, read it, change it, keep it around, and much more.

Let’s look at the main properties you should expect from a DBMS:

• Efficient: a database needs to store and retrieve data quickly.
• Persistent: data stays on disk. When the database software stops or the machine reboots, the data should still be there (hardware failures aside).
• Privacy and security: a database lets you store data privately and securely. Many users can connect, and each one should only see and change what they are allowed to. Some users might read data but not edit or delete it.
• Shared access: with the right permissions, many users can work on the same data. Many applications can talk to the same database too.
• Big: a database can hold huge amounts of data and grow with you using advanced techniques. That does not mean you only need one when you have millions of rows. Even a small table benefits from persistence, security, and shared access.

There are many DBMS products on the market. Some are similar, some are very different.

Relational DBMS, built on the relational model, are the ones you will meet most often in the real world.

Later in this course we will look at three popular open source relational databases: PostgreSQL, MySQL, and SQLite.

If you are not sure which kind of database fits your project, I built a free database chooser that asks a few questions and gives you a recommendation.