A database that maintains a set of separate, related files (tables), but combines data elements from the files for queries and reports when required. The concept was developed in 1970 by Edgar Codd, ...

Database normalization is the cornerstone of database theory. Once a database is normalized, relationships between the data in multiple tables must be established. A hefty part of designing a ...

A question asked about data contained in two or more tables in a relational database. The relational query must specify the tables required and what the condition is that links them; for example, ...

An infant is cuddled and protected by his mother. An adolescent girl is asked out on a date by a boy she had a crush on. A student athlete is carried off the field on the shoulders of his teammates ...