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
Journal ArticleDOI
XCSL: XML constraint specification language
Marta Henriques Jacinto,Giovani Rubert Librelotto,José Carlos Ramalho,Pedro Rangel Henriques +3 more
TL;DR: This paper introduces a domain specific language developed for such a purpose: XCSL, and discusses the general philosophy underlying the proposed approach, presenting the architecture of the semantic vali- dation system, and details the respective processor.
Book ChapterDOI
Object Database Support for Digital Libraries
TL;DR: Some aspects of database support for digital libraries are discussed and a number of improvements to DBMSs that could be beneficial beyond DL applications are suggested.
Book
Algorithmic Learning Theory: 12th International Conference, ALT 2001, Washington, DC, USA, November 25-28, 2001. Proceedings.
TL;DR: This work focuses on the development of efficient learning of Semi-structured Data from Queries in Elementary Formal Systems and on the comparison of Inductive Inference Criteria for Uniform Learning of Finite Classes.
Book ChapterDOI
System of information retrieval in XML documents
TL;DR: This approach supports keyword-based searching like classical IRS and integrates structured searching with the search attributes notion and is based on an indexing method of document tree leafs which authorize a content-oriented retrieval.
Journal ArticleDOI
INode*: an effective approach for storing XML using relational database
Hoi Kit Lau,Vincent To Yee Ng +1 more
TL;DR: This paper presents a new model-mapping method called INode*.
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.