What types of relationships between tables do you know?

Main types of relationships between tables in relational databases:

1. One-to-one (1:1)

   • Each record in the first table is related to one record in the second table and vice versa.
   • Example: the Users table and the Profiles table, where each user has one profile.

2. One-to-many (1:N)

   • One record in the first table is related to multiple records in the second table.
   • Example: the Authors table and the Books table, where one author can have many books.

3. Many-to-many (N:M)

   • Records in the first table can be related to multiple records in the second table and vice versa.
   • Implemented through an intermediate (linking) table.
   • Example: the Students table and the Courses table, where a student can attend multiple courses, and a course can have many students.

Each type of relationship is implemented through keys (primary and foreign) and ensures data integrity and proper organization of information.