Let's take a breather from our normal demo Tic-Tac-Toe game application and look at a few Entity Framework Core 3.0 concepts in a little more detail.

Before you understand and make any advanced queries, it is important to understand what kinds of relationship are possible between two or more entities with respect to data.

We have already looked at the basics in terms of primary keys and foreign keys, but let's go over their definitions, which will help you understand the terms a bit more.