CODEWITHSUNDEEP
sqldatabasephpmyadmincardinality
user3148309
user3148309

Reputation: 71

Having FK and PK on same column? cardinality/SQL

Im learning about databases, I would like to know that is it possible to have a column in a table which gets its Foreign key from another table and at the same time has a primary key?

For example:

X: class, teacher

Y:class(FK,PK)?,teacher

Upvotes: 1

Views: 374

Answers (1)

Mitch Wheat
Mitch Wheat

Reputation: 300719

Yes, it is.

This is often used to represent a 1-1 relationship, or many-to-many relationships when there is a composite primary key across columns which are all foreign keys

The most common place I have seen it is in relationships created by ORMs to represent inheritance.

Upvotes: 3

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