Data Modeling - One-to-One Relationship (bijection)

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1 - About

A one-to-one relationship describe that one row from a dataset point to exactly one row to the other dataset.

There are three way to model a one-to-one relationship:

  • either the associated entities share the same primary keys values,
  • a foreign key is held by one of the entities. This FK column should be constrained unique to simulate one-to-one multiplicity),
  • or an association table is used to store the link between the 2 entities. A unique constraint has to be defined on each FK to ensure the one to one multiplicity.

2 - Article related