(1) The branch of mathematics that deals with relations; for example, AND, OR, NOT, IS and CONTAINS. (2) In a relational database, a collection of rules for dealing with tables; for example, JOIN, ...

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, ...

NoSQL databases are extremely popular among developers thanks to their flexible schemas and rich data types like JSON. But those same attributes make getting data out of them using traditional SQL ...