Relationships between Tables

One core aspect of SQL is the relationships between tables—that is, how different tables relate to each other. There are four relationships in SQL:

• One-to-one
• One-to-many
• Many-to-one
• Many-to-many

One-to-one

A one-to-one relationship occurs when an entity is mapped to another entity uniquely, like when a record in a table maps to only one record in another table. A good example is a relationship between humans and their fingerprints.

In Prisma, we can achieve this with the @relation annotation. First, in the schema.prisma file, we define the model for fingerprints and humans as shown below. The model should include their unique IDs and other relevant information.