Relationships between tables are required for cascading updates or delete statements; these relationships are defined through FOREIGN KEY constraints. (Here’s more information on defining SQL ...

and tables are related through foreign keys. SQL is used to declare the data to be returned, and a SQL query processor and query optimizer turn the SQL declaration into a query plan that is ...

A PERSON has many PERSON ADDRESSes and an ADDRESS has many PERSON ADDRESSes. Across physical tables, shared columns are the evidence of a foreign key relationship. The columns comprising the primary ...