Hara, C. S. & Davidson, S. B. (n.d.), Reasoning about nested functional dependencies, in `PODS'1999', pp. 91--100.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....of Figure 2.2, the scheme tree is shown in Figure 2.4. Nodes of a scheme tree are one or more atomic attributes, and each edge represents an MVD. Besides these functional and multivalued dependencies used in Normal Forms definitions, another definition of functional dependency is presented in [HAR 99] It is called Nested Functional Dependency. The definition of Nested Functional Dependency allows the use of paths in a functional dependency. As an example, the following nested functional dependency can be expressed for the relation of Figure 2.2. DeptCode DeptName EmpCode EmpName FIGURE ....

....The first task consists in defining the functional dependency that will be used in the normal form definition. There are several definitions in literature. Among them are the ones used in the normal form definitions [MAK 77, MOK 96, ROT 88, LIN 89] and the Nested Functional Dependency, defined by [HAR 99] Definition of a concept of normal form: Based in the functional dependency defined in the previous step, the concept of normal form that will be used in the thesis 51 must be defined. Several normal forms for NF relations were proposed in literature: Normal Form (NF) MAK 77] Nested Normal ....

HARA, C.; DAVIDSON, S. Reasoning about nested functional dependencies. In: ACM SYMPOSIUM ON PRINCIPLES OF DATABASE SYSTEMS (PODS), 1999, Philadelphia, Pennsylvania. Proceedings. . .

....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 [13] However, these languages cannot express keys. Generalizations of functional dependencies have also been studied [28, 29]. These constraints are capable of expressing neither foreign keys nor inverse constraints. Furthermore, they were studied in the database context (structured data) Finally, we address the connection between our XML constraints and bounded variable logics, in particular, two variable first order ....

C. Hara and S. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 91--100, Philadephia, Pennsylvania, May 1999.

....In the relational case the canonical instance is isomorphic to the tableau itself. However, in our case, the construction is significantly more complicated due to several reasons: ffl nested sets. While there are some current extensions of the relational tableaux to nested relational tableaux [HD99] these are not enough when we add dictionaries. ffl dictionaries. We choose to give up the nice graphical tableau representation in favor of a graph based construction that is able to represent all reachable components of an object (through record projections or, more complicated, through ....

....containment under Datalog expressible constraints and views [DS96] and containment of non recursive Datalog queries with regular 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 ....

Carmem Hara and Susan Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), Philadelphia, USA, June 1999.

....functional dependency. It is necessary to define the functional dependency that will be used in the normal form definition. There are several definitions in literature. Among them are the ones used in the normal form definitions [20, 23, 12, 19] and the Nested Functional Dependency , defined by [11]. Definition of a concept of normal form. Based in the functional dependency defined in the previous step, the concept of normal form that will be used in the thesis must be defined. Several normal forms for NF relations were proposed in literature: Normal Form (NF) 20] Nested Normal Form (NNF) ....

HARA, C., AND DAVIDSON, S. Reasoning about nested functional dependencies. In ACM Symposium on Principles of Database Systems (PODS) (Philadelphia, Pennsylvania, may 1999).

....even when the path expressions in constraints are simple paths [9] Several practical and decidable cases of the implication problem were identified in [9, 11] Path functional constraints are generalizations of functional dependencies. They were studied for nested relational and object models [17, 18, 25], i.e. in the presence of type constraints. One would be tempted to think that the complexity results for constraint implication established in the typed context would also hold for semistructured data, i.e. in the absence of types. In the typed context one considers graphs whose structures are ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In PODS'99, pages 91--100.

....K are always satisfiable, and for implication of keys, we provide a sound and complete set of inference rules and a cubic time algorithm. Related work. Keys and the more general functional dependencies have been well studied for relational 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 ....

C. Hara and S. Davidson. Reasoning about nested functional dependencies. In Proc. ACM Symp. on Principles of Database Systems (PODS), 1999.

....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 are quite different from the tree model for XML data. Moreover, they cannot express foreign keys. Application of constraints in data transformations was studied in [28] usefulness of keys and foreign keys in query ....

C. Hara and S. Davidson. Reasoning about nested functional dependencies. In PODS'99, pages 91--100.

....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 are quite different from the tree model for XML data considered in this paper. 3 Organization. The rest of the paper is organized as follows. Section 2 defines XML trees, value equality, extended regular path expressions, ....

C. Hara and S. Davidson. Reasoning about nested functional dependencies. In Proc. ACM Symp. on Principles of Database Systems (PODS), pages 91-- 100, 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, ....

....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 extended functional dependencies for nested relations. Another generalization of functional dependencies was investigated for a restricted object oriented data model in [32, 40] These generalizations of functional dependencies are capable of expressing neither foreign keys nor inverse ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 91--100, Philadephia, Pennsylvania, May 1999.

....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 are quite different from the tree model for XML data considered in this paper. Moreover, they cannot express foreign keys. Organization. The reminder of the paper is organized as follows. Section 2 presents a formalism of ....

C. Hara and S. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 91--100, 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 capable of expressing (unary) foreign key constrains. Inverse constrains are also expressible in the languages of [11, 12, 13] ....

....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] studies extended functional dependencies for nested relations. Another generalization of functional dependencies, called path functional dependencies, has been investigated for a restricted object oriented data model in [23, 28] These generalizations of functional dependencies are capable of ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems, pages 91-- 100, Philadephia, 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] ....

....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] studies extended functional dependencies for nested relations. Another generalization of functional dependencies, called path functional dependencies, has been investigated for a restricted object oriented data model in [22, 28] These generalizations of functional dependencies are capable of ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems, pages 91-- 100, Philadephia, 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] ....

....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] studies extended functional dependencies for nested relations. Another generalization of functional dependencies, called path functional dependencies, has been investigated for a restricted object oriented data model in [23, 28] These generalizations of functional dependencies are capable of ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems, pages 91-- 100, Philadephia, Pennsylvania, May 1999.

....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. Note that path constraints for semistructured data and XML are studied in [4, 8, 9, 10] but these do not consider functional dependencies, such as keys. [18] studies extended functional dependencies for nested relations but does not address foreign keys and inverse constraints. Organization. The rest of the paper is organized as follows. Section 2 presents the XML data model with schema and constraints, defines the constraint languages L, L id and ....

C. S. Hara and S. B. Davidson "Reasoning about nested functional dependencies". In Proc. 18th ACM Symp. on Principles of Database Systems (PODS'99), 1999.

....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, which are quite different from the tree model for XML data considered in this paper. Surveys on XML constraints can be found in [13, 34] The remainder of the paper is organized as follows. Section 2 formally defines XML ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 91--100, Philadelphia, Pennsylvania, May 1999.

....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, which are quite di erent from the tree model for XML data considered in this paper. Surveys on XML constraints can be found in [14, 35] The remainder of the paper is organized as follows. Section 2 formally de nes XML trees, ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 91-100, Philadelphia, Pennsylvania, May 1999.

....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 are quite different from the tree model for XML data considered in this paper. Contributions. The main contributions of the paper are the following. ffl We investigate the containment problem for two classes of regular ....

C. S. Hara and S. B. Davidson. Reasoning about nested functional dependencies. In Proceedings of ACM Symposium on Principles of Database Systems (PODS), pages 91--100, May 1999.

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Hara, C. S. & Davidson, S. B. (n.d.), Reasoning about nested functional dependencies, in `PODS'1999', pp. 91--100.

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C. Hara and S. Davidson. Reasoning about nested functional dependencies. In PODS'99, pages 91-100.

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C. Hara and S. Davidson. Reasoning about nested functional dependencies. In PODS'99, pages 91-100.

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