Journal ArticleDOI
The Lorel Query Language for Semistructured Data
Reads0
Chats0
TLDR
The main novelties of the Lorel language are the extensive use of coercion to relieve the user from the strict typing of OQL, which is inappropriate for semistructured data; and powerful path expressions, which permit a flexible form of declarative navigational access and are particularly suitable when the details of the structure are not known to the user.Abstract:
language, designed for querying semistructured data. Semistructured data is becoming more and more prevalent, e.g., in structured documents such as HTML and when performing simple integration of data from multiple sources. Traditional data models and query languages are inappropriate, since semistructured data often is irregular: some data is missing, similar concepts are represented using different types, heterogeneous sets are present, or object structure is not fully known. Lorel is a user-friendly language in the SQL/OQL style for querying such data effectively. For wide applicability, the simple object model underlying Lorel can be viewed as an extension of the ODMG data model and the Lorel language as an extension of OQL. The main novelties of the Lorel language are: (i) the extensive use of coercion to relieve the user from the strict typing of OQL, which is inappropriate for semistructured data; and (ii) powerful path expressions, which permit a flexible form of declarative navigational access and are particularly suitable when the details of the structure are not known to the user. Lorel also includes a declarative update language. Lorel is implemented as the query language of the Lore prototype database management system at Stanford. Information about Lore can be found at http://www-db.stanford.edu/lore. In addition to presenting the Lorel language in full, this paper briefly describes the Lore system and query processor. We also briefly discuss a second implementation of Lorel on top of a conventional object-oriented database management system, the O2 system.read more
Citations
More filters
Proceedings ArticleDOI
Spatio -temporal information integration in XML
TL;DR: A query language based on XML-QL is alsoprovided in support of spatio-temporal queries onXML data and is illustrated with typical query examples.
Proceedings Article
An approach to the visualization of adaptive hypermedia structures and other small-world networks based on hierarchically Clustered Graphs
TL;DR: This dissertation aims to provide a history of magnetism, magnetism and magnetism in the developing world as well as some of the mechanisms that contribute to the formation of Magnetism.
Journal ArticleDOI
Transformation rules for decomposing heterogeneous data into triples
Mrityunjay Singh,S.K. Jain +1 more
TL;DR: This paper has proposed a decomposition algorithm for expressing various heterogeneous data models into the triple model, based on the decomposition theory of the double model, and proposed a set of transformation rules for the existing data models.
Dealing with Complex Patterns in XML Processing
TL;DR: This paper presents an alternative approach that handles many kinds of patterns within the same framework based on the pattern calculus, and shows how programs can be highly parametric over well-typed complex patterns.
Journal ArticleDOI
An extensible information model for shared scientific data collections
Amarnath Gupta,Chaitan Baru +1 more
TL;DR: An information model is defined to support sharing of composite-media scientific data and contains several built-in types such as resolution and derivation link types, to adequately model object relationships in scientific data.
References
More filters
Journal ArticleDOI
Query evaluation techniques for large databases
TL;DR: This survey describes a wide array of practical query evaluation techniques for both relational and postrelational database systems, including iterative execution of complex query evaluation plans, the duality of sort- and hash-based set-matching algorithms, types of parallel query execution and their implementation, and special operators for emerging database application domains.
Book
The object database standard: ODMG 2.0
R. G. G. Cattell,Douglas K. Barry,Dirk Bartels,Mark Berler,Jeff Eastman,Sophie Gamerman,David Jordan,Adam Springer,Henry Strickland,Drew Wade +9 more
TL;DR: With this book, standards are defined for object management systems and this will be the foundational book for object-oriented database product.
Proceedings ArticleDOI
Object exchange across heterogeneous information sources
TL;DR: An object-based information exchange model and a corresponding query language are defined that are well suited for integration of diverse information sources and used to integrate heterogeneous bibliographic information sources.
Book ChapterDOI
Querying Semi-Structured Data
TL;DR: The main purpose of the paper is to isolate the essential aspects of semistructured data, and survey some proposals of models and query languages for semi-structured data.