Database normalization is the cornerstone of database theory. Once a database is normalized, relationships between the data in multiple tables must be established.

In Excel, you can create relationships between two tables based on the matching data within the table. Learn how to create relationships between tables in Excel.

With a relational database, you accomplish this by way of new data columns (for one-to-one or one-to-many relationships), or new tables (for many-to-many relationships).

Get started modeling entities and relationships for Java data persistence, using an example application based on Java 21 with Hibernate 6.3.