Can anyone explain how to implement one-to-one, one-to-many and many-to-many relationships while designing tables with some examples?
Sql – How to implement one-to-one, one-to-many and many-to-many relationships while designing tables
database-designoraclesql
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Best Answer
One-to-one: Use a foreign key to the referenced table:
You must also put a unique constraint on the foreign key column (
addess.student_id
) to prevent multiple rows in the child table (address
) from relating to the same row in the referenced table (student
).One-to-many: Use a foreign key on the many side of the relationship linking back to the "one" side:
Many-to-many: Use a junction table (example):
Example queries: