Follow this step-by-step guide to install PostgreSQL, load data, connect to a database, and execute SQL queries including table joins PostgreSQL is an open-source, object-relational (also called ...

Cascading referential integrity constraints are foreign key constraints that tell SQL Server to perform certain actions when a primary key field in a primary key-foreign key relationship is updated or ...

A primary key is a field used to uniquely identify every record in the database. Sometime primary keys are obvious, for example a car license plate could be used to uniquely identify cars. Often, ...

A primary key is a field used to uniquely identify every record in the database. Sometimes primary keys are obvious, for example a car license plate could be used to uniquely identify cars. Often, ...