What types of relationships have you used in databases? How is a many-to-many relationship implemented?

The following types of relationships are used in databases between tables:

• One-to-one (1:1) — each record in the first table is related to one record in the second.
• One-to-many (1:N) — one record is related to multiple records in another table.
• Many-to-many (M:N) — records from one table can be related to multiple records in another, and vice versa.

A many-to-many relationship is implemented through an intermediate (linking) table that contains foreign keys to both related tables. For example, for the relationship "Students" and "Courses":

Tables:

• students (id, name)
• courses (id, title)
• student_courses (student_id, course_id) — linking table

This approach allows efficient storage and management of multiple relationships between entities.