Beginning XML Databases (Wrox Beginning Guides)

A key is a specialized field determining uniqueness or application of referential integrity through use of primary and foreign keys.

Kludge is a term often used by computer programmers to describe a clumsy or inelegant solution to a problem. The result is often a computer system consisting of a number of poorly matched elements. Too many kludges can shorten the useful life of a system, but sometimes they offer the cheapest remedy to otherwise irresolvable problems or unacceptably costly solutions.