P. Buneman, W. Fan, and S. Weinstein. "Interaction between path and type constraints ". In Proc. 18th ACM Symp. on Principles of Database Systems (PODS'99), 1999.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....when considering D equivalence and D minimality. 2 In a previous paper [12] we derived from a DTD the constraints necessary to show the equivalence of expression (3) to expressions (4) and (5) so called parent and child constraints, respectively. These constraints are simple type constraints [3], rather than path constraints [1] They are also different from the constraints studied in [6] In this paper, we define sibling constraints which generalise child constraints and are necessary to show that expressions (3) and (6) are equivalent. In fact, we show that a reduced XPath expression ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proc. Eighteenth ACM Symp. on Principles of Databases Systems, pages 56--67. ACM Press, 1999.

....expression atoms under a rich class of constraints [CGL98] We are not aware of any extension of the chase to complex values and oodb models. Hara and Davidson [HD99] provide a complete intrinsic axiomatization of generalized functional dependencies for complex value schemas without empty sets. BFW99] examines the un decidability of logical implication for path constraints in various classes of oo typed semistructured models. The maps of [ALPR91] the treatment of object types in [BK93] and in [DHP97] that of views in [dSDA94] and that of arrays in [LMW96] are related to our use of ....

Peter Buneman, Wenfei Fan, and Scott Weinstein. Interaction between Path and Type Constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), Jun 1999.

....modi cations. This diculty has obstructed the use of relational and object oriented approaches to XML data modeling. Therefore, development of an appropriate and ecient data model for XML documents has become an active research area. Major current models are based on directed edge labeled graphs [7, 9, 10, 13, 16], hedge automaton theory [14, 15] and functional programming [12] A declarative description data model for XML documents is developed by employment of Declarative Description (DD) theory [1 3] which has been developed with generality and applicability to data structures of a wide variety of ....

.... set of ODs, whence complex queries about both kind of information can be formulated and executed [6] RDs not only represent relationships among XML elements, but can also be used to de ne integrity constraints that are important in a document, such as data integrity, path and type constraints [10]. Moreover, in order to restrict XML elements to only those that satisfy a given DTD, a simple and e ective mechanism is to directly map the DTD into a corresponding set of RDs for checking the validity of an element with respect to the DTD [5] Sect. 2 reviews major approaches to modeling ....

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Buneman, P., Fan, W., Weinstein, S.: Interaction between Path and Type Constraints. Proc. ACM Symposium on Principles of Database Systems (1999)

....that p q holds from every node reachable from the root by a path in r. Surprisingly, this seemingly benign extension has dramatic impact on the earlier decidability results: the implication problem becomes undecidable even when p; q are words and r is a single letter (The proof, presented in [28], is by reduction of the word problem for finite monoids. Such constraints, as well as extensions allowing to express inverse relationships (e.g. the takes relationship from students to courses is the inverse of the taken by relationship from courses to students) are studied in [27, 28] The ....

....presented in [28] is by reduction of the word problem for finite monoids. Such constraints, as well as extensions allowing to express inverse relationships (e.g. the takes relationship from students to courses is the inverse of the taken by relationship from courses to students) are studied in [27, 28]. The interaction of schemas and constraints is also studied there, and it is shown that schemas have significant impact on the constraint implication problem: some instances of the problem that are decidable in the schema less case become undecidable when schemas are present, and conversely. ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proc. ACM PODS, pages 56--67, 1999.

....and more adequate for XML documents. We mention a third application of the inference of DTDs for XML documents in connection with databases: The importance of making use of DTDs whenever known to optimize the performance of database queries based on XML has been stressed by various authors, see [8, 11, 27, 33, 34]. Unfortunately, DTDs are not always transferred when XML documents are transmitted. Therefore, an automatic generation of DTDs can be also useful in this case, as well. A contribution to the GI community. Finally, one can consider this paper also as a contribution to the GI community: Many GI ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proc. 18th ACM Symposium on Principles of Database Systems (PODS'99), pages 56-67. ACM Press, 1999.

....for the objects composing it. The work in [6] presents a method for the discovery of one level structures (records) in Web pages based on HTML formating tags. More recently, some proposals have been put forward to address the problem of nding structural constraints in semistructured data [13]. Our approach is remarkably distinct from previous works because it relies on the user s perception of the object s structure. That is, instead of trying to derive structural (semantic) matches from the formating (syntax) we induce the user to inform the structure as she he perceives it. We ....

P. Buneman and W. Fan and S. Weinstein. Interaction between Path and Type Constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS) (Philadephia, Pennsylvania, 1999), pp. 56-67.

....programming approaches [13] have failed to directly model XML DTDs and to accommodate such a key functionality. Hence, those models require some significant extensions. For example, applications of schema graphs, first order logic or Datalog rules to the graph model, as presented in [1] [1,11] and [1] respectively, can incorporate a facility for the description of document structuring subject to certain kinds of constraints; however, integration of two different formalisms could make the model complicated and difficult to understand. Important formalisms for the specification of the ....

Buneman, P., Fan, W., Weinstein, S.: Interaction between Path and Type Constraints. Technical Report, Department of Computer and Information Science, University of Pennsylvania (1998) Available at ftp://ftp.cis.upenn.edu/pub/papers/db-research/tr9816.ps.gz

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P. Buneman, W. Fan, and S. Weinstein. "Interaction between path and type constraints ". In Proc. 18th ACM Symp. on Principles of Database Systems (PODS'99), 1999.

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P. Buneman, W. Fan, and S. Weinstein. "Interaction between path and type constraints". In Proc. 18th ACM Symp. on Principles of Database Systems (PODS'99), 1999.

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P. Buneman, W. Fan, and S. Weinstein, Interaction between path and type constraints, Proc. 18th ACM Symp. on Principles of Database Systems , 1999.

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P. Buneman, W. Fan, and S. Weinstein. "Interaction between path and type constraints ". In Proc. 18th ACM Symp. on Principles of Database Systems (PODS'99), 1999.

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P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. ACM Trans. on Computational Logic (TOCL), 4(4):530--577, 2003.

....data [2; 10; 20] In particular, 20] also studies the consistency problem; the special form of constraints used there makes it possible to encode consistency as an instance of conjunctive query containment. The interaction between path constraints and database schemas was investigated in [9]. These constraints typically specify inclusions among certain sets of objects in edge labeled graphs, and are not capable of expressing keys. Various generalizations of functional dependencies have also been studied [23; 25] But these generalizations were investigated in database settings, ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In PODS'99, pages 56-67.

....data [2; 10; 20] In particular, 20] also studies the consistency problem; the special form of constraints used there makes it possible to encode consistency as an instance of conjunctive query containment. The interaction between path constraints and database schemas was investigated in [9]. These constraints typically specify inclusions among certain sets of objects in edge labeled graphs, and are not capable of expressing keys. Various generalizations of functional dependencies have also been studied [23; 25] But these generalizations were investigated in database settings, which ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In _PO/)S, pages 56-67.

....and inverse constraints and their implication by basic XML constraints. It should be mentioned that we only investigated constraint implication that generally holds independently of DTDs. This allows us to study XML documents that do not come with a DTD, and simplifies our proofs. As indicated in [12], integrity constraints may interact with schema (DTDs) and the interaction may not be simple. As a result, constraint implication may have widely different complexities in the presence and absence of a schema, and our proof techniques no longer apply in the typed context. Recently, finite) ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, Philadelphia, Pennsylvania, May 1999.

....in the typed context would still hold for semistructured data. However, the interaction between type and path constraints is far more intriguing. It has been shown that the presence of types may in some cases simplify the implication analysis of path constraints and in other cases make it harder [8]. To illustrate that types may simplify reasoning about path constraints, let us consider a restriction of the objectoriented type system given in Section 1, defined by: t : b j C : t j [l 1 : t 1 ; l n : t n ] where b and C are atomic and class types, respectively. This type ....

....these simple structures, which yields a simpler analysis. Indeed, let us consider the class of P p inc constraints in which path expressions are restricted to be simple paths, referred to as P s inc . In this typed context, the implication problem for P s inc is decidable in O(n 3 ) time [8], whereas it is undecidable in the context of semistructured data [9] On the other hand, there is a path constraint implication problem that is decidable in the untyped context but it becomes undecidable in a typed context. In particular, let us consider a set Sigma of P s inc constraints of ....

[Article contains additional citation context not shown here]

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In PODS'99, pages 56--67.

.... knowledge, no previous work has considered the interaction between DTDs, and keys and foreign keys for XML (in the tree model) A variety of path constraints have been studied for semistructured and XML data [2, 9] The interaction between path constraints and database schemas was investigated in [8]. Path constraints specify inclusions among certain sets of objects in edge labeled graphs, and are not capable of expressing keys. Various generalizations of functional dependencies have also been studied, see, for example, 18, 19] But these generalizations were investigated in database ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In PODS'99, pages 56--67.

....studied in the absence [21] and presence [20] of DTDs. The keys considered there are defined in terms of XML attributes and are not as expressive as keys studied in this paper. 2 Integrity constraints defined in terms of navigation paths have been studied for semistructured [3] and XML data in [5, 14, 15, 16]. These constraints are generalizations of inclusion dependencies commonly found in relational databases, and are not capable of expressing keys. Generalizations of functional dependencies have also been studied [23, 26, 33] However these generalizations were investigated in database settings, ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, Philadelphia, Pennsylvania, May 1999.

.... and object oriented databases (see [2] for a survey and [16, 17, 19] for recent work) As observed by [8, 7] these constraint specifications are not appropriate for XML data and the complexity results in connection with reasoning about these constraints no longer hold in the XML setting [9, 12]. Key specifications for XML have been proposed in the XML standard (DTD) 5] XML Schema [20] and in a recent proposal [7] One can view ID attributes in a DTD as keys. This key specification is rather weak. First, IDs can only be specified in DTDs and thus do not help documents without a DTD. ....

....shown that the implication problem for the key language is finitely axiomatizable and cubic time decidable. A number of questions remain open. First, the decision problems are investigated in the absence of DTDs. Keys may interact with DTDs and the interaction may complicate reasoning about keys [12, 9]. This issue needs further investigation. Second, keys help information preservation in data exchange and integration. An important project is to study how to achieve this in practice. Third, keys may lead to efficient storage and access methods for XML data. This practical issue deserves further ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proc. ACM Symp. on Principles of Database Systems (PODS), 1999.

....data [2, 10, 20] In particular, 20] also studies the consistency problem; the special form of constraints used there makes it possible to encode consistency as an instance of conjunctive query containment. The interaction between path constraints and database schemas was investigated in [9]. These constraints typically specify inclusions among certain sets of objects in edge labeled graphs, and are not capable of expressing keys. Various generalizations of functional dependencies have also been studied [23, 25] But these generalizations were investigated in database settings, which ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In PODS'99, pages 56--67.

....studied in the absence [22] and presence [21] of DTDs. The keys considered there are de ned in terms of XML attributes and are not as expressive as keys studied in this paper. 2 Integrity constraints de ned in terms of navigation paths have been studied for semistructured [3] and XML data in [5, 15, 16, 17]. These constraints are generalizations of inclusion dependencies commonly found in relational databases, and are not capable of expressing keys. Generalizations of functional dependencies have also been studied [24, 27, 34] However these generalizations were investigated in database settings, ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56-67, Philadelphia, Pennsylvania, May 1999.

.... knowledge, no previous work has considered the interaction between DTDs, and keys and foreign keys for XML (in the tree model) A variety of path constraints have been studied for semistructured and XML data [2, 9] The interaction between path constraints and database schemas was investigated in [8]. Path constraints specify inclusions among certain sets of objects in edge labeled graphs, and are not capable of expressing keys. Various generalizations of functional dependencies have also been studied, see, for example, 18, 19] But these generalizations were investigated in database ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In PODS'99, pages 56-67.

....The key constraints considered in those papers are defined in terms of XML attributes and are not as expressive as keys studied in this paper. We do not consider foreign keys and DTDs here. Constraints defined in terms of navigation paths have been studied for semistructured [1] and XML data in [3, 9, 10, 11, 12]. These constraints are generalizations of inclusion dependencies commonly found in relational databases, and are not capable of expressing keys. Generalizations of functional dependencies have also been studied [20, 23, 28] But these generalizations were investigated in database settings, which ....

....implication problems for the key language are finitely axiomatizable and are decidable in cubic time. A number of questions remain open. First, the decision problems are investigated in the absence of XML DTDs. Keys may interact with DTDs and the interaction may complicate reasoning about keys [17, 16, 10]. This issue needs further investigation. Second, keys also interact with foreign keys. As shown by [18] the (finite) implication problem for simple keys and foreign keys is undecidable even in the context of relational databases. It is important to find practical restrictions under which the ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proc. ACM Symp. on Principles of Database Systems (PODS), pages 56--67, 1999.

....to reason about efficiently, and add these constraints as a minimum extension to XML DTDs. We investigate more expressive constraints that can be derived or implied by basic XML constraints, such as constraints defined in terms of navigation paths. Path constraints have been studied formally in [4, 12, 13, 14, 11, 31, 32, 40]. The path constraint languages introduced in [4, 12, 13, 14, 11] specify inclusions among certain sets of objects, and were studied for semistructured data and XML. They are generalizations of (unary) inclusion dependencies. Inverse constrains are also expressible in the languages of [12, 13, 14, ....

....to XML DTDs. We investigate more expressive constraints that can be derived or implied by basic XML constraints, such as constraints defined in terms of navigation paths. Path constraints have been studied formally in [4, 12, 13, 14, 11, 31, 32, 40] The path constraint languages introduced in [4, 12, 13, 14, 11] specify inclusions among certain sets of objects, and were studied for semistructured data and XML. They are generalizations of (unary) inclusion dependencies. Inverse constrains are also expressible in the languages of [12, 13, 14, 11] However, these languages cannot express keys. 31] studies ....

[Article contains additional citation context not shown here]

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, Philadelphia, Pennsylvania, May 1999.

....As mentioned earlier, in the relational setting, the finite satisfiability problem for keys and foreign keys is trivial. A variety of path constraints have been studied for semistructured and XML data [2, 8, 10] The interaction between path constraints and database schemas was investigated in [9]. Path constraints specify inclusions among certain sets of objects in edge labeled graphs. They are not capable of expressing key constraints. Organization. The reminder of the paper is organized as follows. Section 2 presents a formalism of XML DTDs, describes the tree model for XML, and defines ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, Philadelphia, Pennsylvania, May 1999.

....shows that finite implication problem associated with the simpler unary keys and foreign keys for XML is coNP complete. A variety of path constraints have been studied for semistructured and XML data [2, 9, 11] The interaction between path constraints and database schemas was investigated in [10]. Path constraints specify inclusions among certain sets of objects in edge labeled graphs. They are not capable of expressing keys. Organization. The rest of the paper is organized as follows. Section 2 describes a formalism of XML DTDs and defines two classes of keys and foreign keys for XML, ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, Philadelphia, Pennsylvania, May 1999.

....XML DTDs and these constraints. The key constraints considered in these papers are defined in terms of XML attributes and are therefore not as expressive as the keys studied in this paper. Constraints defined in terms of navigation paths have been studied for semistructured [1] and XML data in [3, 9, 10, 11, 12]. These constraints are generalizations of inclusion dependencies commonly found in relational databases, and are not capable of expressing keys. Generalizations of functional dependencies have also been studied [18, 21] However these generalizations were investigated in database settings, which ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, May 1999.

....of our knowledge, no previous work has considered the interaction between DTDs and key, foreign key constraints for XML. A variety of path constraints have been studied for semistructured and XML data [2, 9, 11, 12] The interaction between path constraints and database schemas was investigated in [10]. Path constraints specify inclusions among certain sets of objects in edge labeled graphs. They are not capable of expressing key constraints. Generalizations of functional dependencies have also been studied [25, 27, 40] But these generalizations were investigated in database settings, which ....

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 56--67, Philadelphia, Pennsylvania, May 1999.

....with many natural constraints are undecidable. For example, these problems are undecidable for the simple constraint language P c introduced in [11 13] In addition, we have already studied the connection between object oriented databases and semistructured databases in SM with P c constraints [12]. The results of [12] show that the connection is not simple. In this paper, we investigate path constraints for DM . We demonstrate applications of path constraints to semantic specification and query optimization, and study the implication problems associated with path constraints. We show that ....

....constraints are undecidable. For example, these problems are undecidable for the simple constraint language P c introduced in [11 13] In addition, we have already studied the connection between object oriented databases and semistructured databases in SM with P c constraints [12] The results of [12] show that the connection is not simple. In this paper, we investigate path constraints for DM . We demonstrate applications of path constraints to semantic specification and query optimization, and study the implication problems associated with path constraints. We show that in contrast to the ....

[Article contains additional citation context not shown here]

P. Buneman, W. Fan, and S. Weinstein. "Interaction between path and type constraints ". In Proc. 18th ACM Symp. on Principles of Database Systems (PODS'99), 1999.

....problems. This also highlights the importance of path constraints in this context. As an example, we would like to know that isbn is not only a key for entry, but also a key for the outer book elements. This never occurs in the relational setting. Path constraints have been studied formally in [4, 11, 12, 13, 22, 23, 28]. The path constraint languages introduced in [4, 11, 12, 13] specify inclusions among certain sets of objects, and are studied for semistructured data and XML. They are capable of expressing (unary) foreign key constrains. Inverse constrains are also expressible in the languages of [11, 12, 13] ....

....context. As an example, we would like to know that isbn is not only a key for entry, but also a key for the outer book elements. This never occurs in the relational setting. Path constraints have been studied formally in [4, 11, 12, 13, 22, 23, 28] The path constraint languages introduced in [4, 11, 12, 13] specify inclusions among certain sets of objects, and are studied for semistructured data and XML. They are capable of expressing (unary) foreign key constrains. Inverse constrains are also expressible in the languages of [11, 12, 13] However, these languages cannot express key constraints. 22] ....

[Article contains additional citation context not shown here]

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems, pages 56--67, Philadelphia, Pennsylvania, may 1999.

....problems. This also highlights the importance of path constraints in this context. As an example, we would like to know that isbn is not only a key for entry, but also a key for the outer book elements. This never occurs in the relational setting. Path constraints have been studied formally in [4, 10, 11, 12, 21, 22, 28]. The path constraint languages introduced in [4, 10, 11, 12] specify inclusions among certain sets of objects, and are studied for semistructured data and XML. They are generalizations of (unary) inclusion dependencies. Inverse constrains are also expressible in the languages of [10, 11, 12] ....

....context. As an example, we would like to know that isbn is not only a key for entry, but also a key for the outer book elements. This never occurs in the relational setting. Path constraints have been studied formally in [4, 10, 11, 12, 21, 22, 28] The path constraint languages introduced in [4, 10, 11, 12] specify inclusions among certain sets of objects, and are studied for semistructured data and XML. They are generalizations of (unary) inclusion dependencies. Inverse constrains are also expressible in the languages of [10, 11, 12] However, these languages cannot express key constraints. 21] ....

[Article contains additional citation context not shown here]

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems, pages 56--67, Philadelphia, Pennsylvania, May 1999.

....problems. This also highlights the importance of path constraints in this context. As an example, we would like to know that isbn is not only a key for entry, but also a key for the outer book elements. This never occurs in the relational setting. Path constraints have been studied formally in [4, 11, 12, 13, 22, 23, 28]. The path constraint languages introduced in [4, 11, 12, 13] specify inclusions among certain sets of objects, and are studied for semistructured data and XML. They are generalizations of (unary) inclusion dependencies. Inverse constrains are also expressible in the languages of [11, 12, 13] ....

....context. As an example, we would like to know that isbn is not only a key for entry, but also a key for the outer book elements. This never occurs in the relational setting. Path constraints have been studied formally in [4, 11, 12, 13, 22, 23, 28] The path constraint languages introduced in [4, 11, 12, 13] specify inclusions among certain sets of objects, and are studied for semistructured data and XML. They are generalizations of (unary) inclusion dependencies. Inverse constrains are also expressible in the languages of [11, 12, 13] However, these languages cannot express key constraints. 22] ....

[Article contains additional citation context not shown here]

P. Buneman, W. Fan, and S. Weinstein. Interaction between path and type constraints. In Proceedings of ACM Symposium on Principles of Database Systems, pages 56--67, Philadelphia, Pennsylvania, May 1999.

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