F. Bry and S. Scha#ert. Towards a declarative query and transformation language for XML and semistructured data: Simulation unification. In Proc. of International Conference on Logic Programming (ICLP), number 2401 in LNCS, Copenhagen, Denmark, 2002. Springer.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....These documents rely on non linguistic structures, such as HTML XML tags, and sometimes use ungrammatical language to convey information, making the methods appropriate for grammatical text unusable. While there are several query languages supporting the extraction of information from web data [5, 57], their use is time consuming and requires nontrivial skill. As argued for example in [41, 33] there is a need for systems that can learn to extract information from a few annotated examples. The reason is that building IE systems manually is not feasible and scalable for such a dynamic and ....

....systems can be found in [3, 24] They apply knowledge engineering techniques for building wrappers. Manually building a wrapper for each data source becomes infeasible when confronted with the variety of Web sources. A separate area aims at the development of query languages for HTML XML, e.g. [5, 57]. While these query languages are suitable for expressing complex extraction problem, their use remains time consuming and requires non trivial skill. The advantage over other manual approaches is that they provide the user with a sophisticated user interface that simplifies the wrapper ....

F. Bry and S. Schaffert. Towards a declarative query and transformation language for XML and semistructured data: Simulation unification. In Proceedings of the International Conference on Logic Programming, 2002.

....the database item. This paper further investigates using query patterns. It describes Xcerpt, a query and transformation language for XML. Salient features of Xcerpt are the following: 1. Instead of (a form of) pattern matching, a (non standard form of) unification, called simulation unification [7], is used giving rise to make two query patterns both with variables identical. 2. Within an Xcerpt query pattern, a variable may be constrained to a (sub )pattern. 3. The paradigm of Xcerpt is that of SQL and of logic programming. Thus, a query might have several answers. Some of (all, resp. ....

....AUTHOR = Serge Abiteboul and TITLE = Data on the Web on the other hand. Xcerpt evaluation of query terms is based on a non standard evaluation called Simulation Unification. This form of unification, which is intuitively described on examples in the present article, is formally addressed in [7]. 3.3 The Construct # ( as ) In Example 7, variables are leafs (i.e. atomic sub terms) of the query term. In Xcerpt, a variable can also occur at a higher position in a query term and be assigned a lower bound in form of a sub term constraining the bindings for the variable. Example 8. ....

[Article contains additional citation context not shown here]

Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proceedings of the Int. Conf. on Logic Programming (ICLP), Copenhagen, Springer-Verlag LNCS (2002)

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BRY, F., AND SCHAFFERT, S. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Proceedings of International Conference on Logic Programming, Copenhagen, Denmark (29th July--1st August 2002.

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Francois Bry and Sebastian Scha#ert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Peter J. Stuckey (Ed.): Logic Programming, 18 International Conference on Logic Programming (ICLP), Denmark, July, Lecture Notes in Computer Science 2401, Springer-Verlag, 2002.

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Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proc. Int. Conf. on Logic Programming (ICLP). LNCS 2401, Springer-Verlag (2002)

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Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proc. Int. Conf. on Logic Programming (ICLP). LNCS 2401, Springer-Verlag (2002)

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Francois Bry and Sebastian Scha#ert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Proceedings of International Conference on Logic Programming, Copenhagen, Denmark (29th July--1st August 2002), volume 2401 of LNCS, 2002.

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F. Bry and S. Schaert. Towards a declarative query and transformation language for XML and semistructured data: Simulation uni cation. In Intl. Conf. on Logic Programming (ICLP), pages 255-270, 2002.

....of its bindings. The Xcerpt construct desc (read descendant not illustrated above) is used to specify subterms at arbitrary depth. Query terms are unified with database or construct terms using a nonstandard unification called simulation unification, which has been investigated in [12]. Simulation unification is based on graph simulation [13] which is similar to graph homomorphisms. The outcome of unifying a query term with a database term are bindings for the variables in the query term. Applying these bindings to the query term results in a ground query term which is ....

....to querying semistructured data has first been presented in the language UnQL [4] However, UnQL rules may not be connected by chaining and 13 lack many of the constructs found in Xcerpt. Several publications concerning the language design and semantics of Xcerpt are available, in particular [5,15,12,16]. Visual XML query languages that the authors are aware of are XML GL [6] GraphLog [7] VXT [8] BBQ [9] and Xing [10] Most of these languages visualize the XML document as a tree (i.e. nodes connected with arrows or similar) While on first look this appears to be very concise, it does not ....

Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proc. Int. Conf. on Logic Programming (ICLP). LNCS 2401, Springer-Verlag (2002)

.... number [ AF2 ] 5.2 Rooted Simulation A notion of rooted simulation is used below in Section 5.3 in formalising the satisfaction of semistructured expressions and atomic formulas in an interpretation. The following definition is inspired from [7,8] and refines the simulation considered in [9]. Recall that a (directed) rooted graph G (V, E, r) consists in a set V of vertices, a set E of edges (i.e. ordered pairs of vertices) and a vertex r called the root of G such that there is in G a path from r to each vertex of G. Definition 1 (Rooted Graph Simulation) Let G (V,E,r) and G2 ....

....amenable to declarative programming, especially to logic programming. The entailment introduced in the previous sections has been conceived so as to support such applications that are briefly described below. It provides with the semantics of a prototype Web query language called Xcerpt [9,13]. Dynamic Web pages. Dynamic Web pages are texts or data that are dynamically generated when called. They make it possible for different pages to share data thus ensuring data consistency and to generate up to date Web pages from changeable data. Arguably, logic programming queries would be as ....

[Article contains additional citation context not shown here]

Bry, F., Schaffert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proc. Int. Conf. on Logic Programming. LNCS, Springer-Verlag (2002)

....calendar systems and conversion between their concepts. 4 Perspectives The TemPTo model has been designed as a temporal type system of temporal types for the Web query and transformation language Xcerpt. This type system as well as its addition to Xcerpt are currently under development. Xcerpt [13, 11, 10, 12] is a logic based language currently developed and tested on Web based systems at the University of Munich. Because of its logic bias Xcerpt appears to be a very convenient host for temporal data types and temporal reasoning. Further investigations will show whether the temporal model TemPTo ....

Francois Bry and Sebastian Scha#ert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Peter J. Stuckey (Ed.): Logic Programming, 18 International Conference on Logic Programming (ICLP), Denmark, July, Lecture Notes in Computer Science 2401, Springer-Verlag, 2002.

....uses term variables for this purpose. In [8] a query and transformation language is described that is related to logic and Prolog. This language has (in the terminology used above) only label variables. In contrast, the basic query language introduced above also has term variables. The article [13] describes a non standard unification algorithm subjacent to Definition 9. 14,15] introduce in more detail the query language Xcerpt which builds upon the basic language constructs introduced above. Xcerpt has construct terms in which variables but no desc and may occur. A construct term with ....

Bry, F., Schaffert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proceedings of the Int. Conf. on Logic Programming (ICLP), Copenhagen, Springer-Verlag LNCS (2002)

....term, it is possible to specify subterms at arbitrary depth. Example: This query term selects titles and authors: bib book var T # title, authors var A 2 Query terms are unified with database or construct terms using a non standard unification called simulation unification [11]. It is based on graph simulation [12] which is similar to graph homomorphisms. The outcome of unifying a query term with a database term are bindings for the variables in the query term. Applying these bindings to the query term results in a ground query term which is simulated (in the sense of ....

Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proc. Int. Conf. on Logic Programming (ICLP). LNCS 2401, Springer-Verlag (2002)

.... The following query term queries the amazon.comdatabase for titles and authors and bind the variables TITLE and AUTHOR to the corresponding values in the bn.comdatabase: bib book title TITLE , author AUTHOR The evaluation strategy of Xcerpt is based on simulation unification [2]. The two variables TITLE and AUTHOR will have several possible bindings as a result of the simulation unification, representing all valid combinations of a title with an author that can be found in the database, e.g. AUTHOR= Dan Suciu and TITLE= Data on the Web or AUTHOR= Serge Abiteboul and ....

....at a higher position in a query term: Example 4. The following Xcerpt query binds the variable TITLE to the compound element title . thus retrieving title elements (instead of their content) bib book TITLE # title, author AUTHOR Thanks to simulation unification [2], the leaf of a title element does not have to be explicitly mentioned in the query of Example 4 for being included in the answers. The descendant construct serves to express indefiniteness: Example 5. The following Xcerpt query retrieves the titles of books with an author Stevens at any ....

[Article contains additional citation context not shown here]

Francois Bry and Sebastian Scha#ert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Proceedings of the Int. Conf. on Logic Programming (ICLP), Copenhagen, 2002. Springer-Verlag LNCS 2401.

....considered. An Xcerpt program consists of a finite set of (construct query) rules with a (conjunction of) query term(s) The scope of an occurrence of a variable in an Xcerpt program is, like in Prolog, restricted to the rule it occurs in. 2. 5 Further Features The full version of this paper [8] describes in more details further features of the experimental language Xcerpt, among others the construct all mentioned in the introduction. 3 Simulation Unification The rule based language Xcerpt, the main elements of which have been introduced above in Section 2, can be processed by both ....

.... simulation unification is defined in this paper under the assumptions that are the only kinds of braces, and that braces are only allowed immediately on the right of a label (like in f a, g b, c , d ) and not directly within other braces (like in f a, b, c , d ) The full article [8] explains how to skip these restrictions. 3.1 Simulation Intuitively, a simulation of a graph G 1 in a graph G 2 is a mapping of the nodes of G 1 in the nodes of G 2 preserving the edges. In other words, there exists a simulation of G 1 in G 2 , if the node edge structure of G 1 can be found as ....

[Article contains additional citation context not shown here]

Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. Technical Report PMS-FB-20022, http://www.pms.informatik.uni-muenchen.de/publikationen/#PMS-FB-2002-2 (2002)

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F. Bry and S. Scha#ert. Towards a declarative query and transformation language for XML and semistructured data: Simulation unification. In Proc. of International Conference on Logic Programming (ICLP), number 2401 in LNCS, Copenhagen, Denmark, 2002. Springer.

No context found.

F. Bry and S. Scha#ert. Towards a declarative query and transformation language for XML and semistructured data: Simulation unification. In Proc. of International Conference on Logic Programming (ICLP), number 2401 in LNCS, Copenhagen, Denmark, 2002. Springer.

No context found.

F. Bry and S. Scha#ert. Towards a declarative query and transformation language for Xml and semistructured data: Simulation unification. In Proc. of Iclp, number 2401 in Lncs. Springer, 2002.

No context found.

F. Bry and S. Scha#ert. Towards a declarative query and transformation language for XML and semistructured data: Simulation unification. In Proc. of ICLP, number 2401 in LNCS, Copenhagen, Denmark, 2002. Springer.

No context found.

F. Bry and S. Scha#ert. Towards a declarative query and transformation language for XML and semistructured data: Simulation unification. In Proc. of ICLP, number 2401 in LNCS, Copenhagen, Denmark, 2002. Springer.

No context found.

Francois Bry and Sebastian Scha#ert. Towards a declarative query and transformation language for XML and semistructured data: simulation unification. In Proc. of the 2002 International Conference on Logic Programming, 2002.

No context found.

F. Bry and S. Scha#ert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In International Conference on Logic Programming (ICLP), volume 2401 of LNCS, 2002.

No context found.

Bry, F., Scha#ert, S.: Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In: Proc. Int. Conf. on Logic Programming. LNCS 2401, Springer-Verlag (2002)

No context found.

F. Bry and S. Scha#ert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Proc. of the Int'l Conference on Logic Programming (ICLP'02), volume 2401 of LNCS. Springer-Verlag, 2002.

No context found.

Franois Bry and Sebastian Schaffert. Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification. In Proceedings of the International Conference on Logic Programming (ICLP), Copenhagen, Denmark, July 2002. Springer-Verlag, LNCS 2401.

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