XQuery
XQuery is a query and functional programming language designed for querying and transforming collections of structured and semi-structured data, particularly XML documents. It is standardized by the W3C and provides a way to extract and manipulate data from XML sources, similar to how SQL is used for relational databases. XQuery can be used for tasks such as searching, filtering, and generating XML or other text-based outputs.
Developers should learn XQuery when working extensively with XML data, such as in content management systems, web services (e.g., SOAP), or data interchange formats, as it offers powerful querying capabilities tailored for hierarchical structures. It is particularly useful in scenarios requiring complex data extraction from large XML datasets, integration with XML databases like eXist-db, or when implementing XSLT-like transformations with a more SQL-like syntax. For example, in publishing or financial industries where XML is prevalent, XQuery enables efficient data processing and reporting.