In computing, a schema is an outline or diagram that describes the structure of a specific type of data. Schemas are most often used to describe XML files and databases, but they can describe many other types of data as well.

An XML schema includes an ordered list of elements that an XML file may contain. This specific structure ensures multiple related XML documents follow a strict syntax and do not contain unknown data. By following a specific schema, XML files can be easily parsed by a script or application.

Database schemas are often used to provide a visual representation of the tables and records contained in a database. Tables are displayed as boxes, which each include a list of fields. Lines are used to connect tables within the database and show how data flows between the tables. Database schemas often include comments that describe the tables and fields and may include labels that identify primary and unique keys within each table.

Updated: May 18, 2013