Database Relationships

Database Relationships: Database Relationships: an overview, One-to-Many, One-to-One, Many-to-Many.

Updated

  1. Database Relationships: an overview (Apprentice): The three kinds of relationship between tables (one-to-many, one-to-one and many-to-many) and how a diagram shows each.
  2. One-to-Many (Apprentice): How a one-to-many relationship links many child rows to one parent row through a foreign key, like a customer and their orders.
  3. One-to-One (Apprentice): How a one-to-one relationship uses the child table's primary key as its foreign key, and why you would move rarely used data into its own table.
  4. Many-to-Many (Journeyman): Why two tables can't link many-to-many directly, and how an associative (junction) table between them turns it into two one-to-many relationships.