Definition
A query language for semi-structured data allows a user to extract items from a semi-structured data instance, or to transform it into another semi-structured data instance. The first type of expressions are called queries, the latter kind of expressions are interchangeably called queries or transformations. Query languages can be classified along several dimensions:
- 1.
Expressive power. What kind of queries or transformations can they express?
- 2.
Querying vs. restructuring. Some query languages allow only the extraction of items from the data, others allow the data to be transformed.
- 3.
Compositionality. Can the output of a query be used as input in another query expressed in the language, and is the composed transformation still expressible in the same language? Query languages that are restricted to extraction only are not compositional, because the type of their outputs are not semi-structured data instances. Transformation languages may fail to be compositional if the...
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsRecommended Reading
Abiteboul S, Quass D, McHugh J, Widom J, Wiener J. The Lorel query language for semistructured data. 1996. http://www-db.stanford.edu/lore/.
Buneman P, Davidson S, Suciu D. Programming constructs for unstructured data. In: Proceedings of the Workshop on Database Programming Languages; 1995.
Deutsch A, Fernandez M, Florescu D, Levy A., Suciu D. A query language for XML. In: Proceedings of the 8th International World Wide Web Conference; 1999. p. 77–91.
Fernandez M, Florescu D, Kang J, Levy A, Suciu D. Catching the boat with Strudel: experience with a Web-site management system. In: Proceedings of the ACM SIGMOD International Conference on Management of Data; 1998. p. 414–25.
Papakonstantinou Y, Abiteboul S, Garcia-Molina H. Object fusion in mediator systems. In: Proceedings of the 22th International Conference on Very Large Data Bases; 1996. p. 413–24.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Section Editor information
Rights and permissions
Copyright information
© 2018 Springer Science+Business Media, LLC, part of Springer Nature
About this entry
Cite this entry
Suciu, D. (2018). Semi-structured Query Languages. In: Liu, L., Özsu, M.T. (eds) Encyclopedia of Database Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-8265-9_339
Download citation
DOI: https://doi.org/10.1007/978-1-4614-8265-9_339
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-8266-6
Online ISBN: 978-1-4614-8265-9
eBook Packages: Computer ScienceReference Module Computer Science and Engineering