Zo'e Lacroix, Claude Delobel, and Philippe Br`eche. Object views and database restructuring. In Sophie Cluet and Richard Hull, editors, Database Programming Languages, 6th International Workshop, DBPL6, Estes Park, Colorado, USA, August 18-20,  Home/Search   Document Details and Download   Summary   Related Articles   Check

....preserving the good performance and scalability properties of the current solution. To our knowledge, there is no previous work on views in a web scale heterogeneous information system. Previous works provided view mechanisms with more powerful definition languages for relational [11, 14] object [10], semistructured [1] databases or mediators [9, 7] but their are not adapted to heterogeneity on a large scale. The paper is organized as follows. In Sections 2 to 4, we address the problems of, respectively, i) definition, ii) implementation and (iii) translation of views. In Section 5, we ....

Zo'e Lacroix, Claude Delobel, and Philippe Br`eche. Object views and database restructuring. In Sophie Cluet and Richard Hull, editors, Database Programming Languages, 6th International Workshop, DBPL6, Estes Park, Colorado, USA, August 18-20,

....identifiers (oids) The schema also provides value classes (string, integer, etc. populated with constants. We also assume that the reader is familiar with the concepts of object oriented databases as presented in [AHV95] AKIRA s view mechanism is inspired by the view mechanism introduced in [LDB97] In this section we give a informal description of some of the specifics of our approach. 3.1 Fragments AKIRA replaces the standard browser cache by a Web view. A cache usually stores HTML pages in a dummy file system where manipulation is based on page names. Even for the database community, ....

....x , x in Fragment, z in Appointment where z.URL = x .URL = x .URL x in z.person.REFERSTO x in z.position.REFERSTO 3. 3 View mechanism Our view mechanism goes through a pipeline (see Figure 2) of successive and interleaved materialized views (obtained by successive materialized extensions [dS95, LDB97] Initially, class Fragment is supposed to be populated with data retrieved from the Web. Afterwards, each step derives a Web view from a Web view through an extension step. An extension consists in adding structure (concepts classes, organized in a hierarchy, and attributes defined at these ....

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Z. Lacroix, C. Delobel, and Ph. Br`eche. Object Views and Database Restructuring. In Proc. of Intl. Workshop on Database Programming Languages, august 1997.

....object oriented database instance. The object schema consists of classes, a class hierarchy (subclassing relationship) attributes and methods with their signatures. Classes are populated with object identifiers (oids) AKIRA s view mechanism is inspired by the view mechanism introduced in [dSDA94,LDB97] 3.1 Motivating example Researchers are usually interested in Calls for Papers (CFPs) in subject areas related to their research. While CFPs are widely disseminated, being published in journals, newsgroups, mailing lists etc. researchers would appreciate a facility to find out about relevant ....

....in Conference where c. temperature 90 the OQL expression: select c.name from c in Conference where c.country.temperature 90 3. 4 View mechanism Our view mechanism goes through a pipeline (see Figure 3) of successive and interleaved views (obtained by successive materialized extensions [dSDA94,LDB97] The main task consists in specifying the schema transformation from the current schema to the target structure. When the first query is asked, the current schema is empty. In case of a refinement, a current schema (defined to answer previous queries) structures the cache and has to be extended ....

Z. Lacroix, C. Delobel, and Ph. Br`eche. Object Views and Database Restructuring. In Proc. of Intl. Workshop on Database Programming Languages, August 1997.

....a class hierarchy (subclassing relationship) attributes and methods. Classes are populated with object identifiers (oids) The schema also provides value classes (string, integer, etc. populated with constants. AKIRA s view mechanism is inspired by the view mechanism introduced in [dSDA94, LDB97] In this section we give a informal description of some of the specifics of our approach. 3.1 Fragments AKIRA replaces the standard browser cache by a Web view. A cache usually stores HTML pages in a dummy file system where manipulation is based on page names. Even for the database community, a ....

....agent capable of matching a given icon to an element in an icon library by similarity (in the spirit of [Jag96] 3. 3 View mechanism Our view mechanism goes through a pipeline (see Figure 4) of successive and interleaved materialized views (obtained by successive materialized extensions [dSDA94, LDB97] Initially, class Fragment is supposed to be populated with data retrieved from the Web. Afterwards, each step derives a Web view from a Web view through an extension step. An extension consists in adding structure (concepts classes, organized in a hierarchy, and attributes defined at these ....

[Article contains additional citation context not shown here]

Z. Lacroix, C. Delobel, and Ph. Br`eche. Object Views and Database Restructuring. In Proc. of Intl. Workshop on Database Programming Languages, August 1997.

....of the given source(s) of documents. It is built on the fly according to the user s needs as explained in Section 3. As defined in Section 4, our view mechanism goes through a pipeline of materialized views, obtained by successive materialized extensions and non materialized projections [dSDA94, LDB97] 2 Conceptualization of extraction capabilities We consider three extraction capabilities: extracting concepts, meta concepts and attributes which we represent in an abstract way in a pool of schema components. 2.1 Extraction capabilities Extracting a concept goes beyond the usual retrieval ....

....of the output: it is a perfect candidate for a schema of our object database. 3. 3 From a conceptual schema to an object schema We assume the reader is familiar with the concepts of object oriented databases as presented in [AHV95] We adopt the formalism of the data model presented in [LDB97] Our approach is user oriented: it does not pre suppose any schema already defined in the object database. The modularity of IE tools thus corresponds to the modularity of an approach building an object schema on the fly with respect to the user s conceptual representation expressed in his ....

[Article contains additional citation context not shown here]

Z. Lacroix, C. Delobel, and Ph. Br`eche. Object Views and Database Restructuring. In Proc. of Intl. Workshop on Database Programming Languages, August 1997.

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