Types of Databases - Object Oriented
For example, imagine you're a police officer looking for a patient in a hospital ... but the only information you have to go on is that the patient's first name is John.
If you searched for John in the "kinds" or class list of the hospital's OOD, likely every person named "John" who has ever visited the hospital would come up.
But if you first searched the "parts" or object list looking for Patient ID's and today's date and then combined that information with a search for "John", only the names of recent patients named John would appear.
As you can see, our four types of databases look at data in different ways ...
A good programmer will be able to find the right database application for your situation.