S. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, Univ. of Wisconsin, 1993.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....algebra which allows the manipulation of sets. The select operation is the same as in the collection algebra. The imagine operation is the same as iter in Machiavelli. The flatten operation can be expressed as applying iter of the collection algebra with an identity function. The EXCESS algebra [38] is an object algebra supporting bags and arrays. The set collapse and set apply operations are the bag equivalent of flatten and iter in EQUAL. While arr apply is the array version of EQUAL s iter. However, no operation is provided for conversion between collection kinds. Properties of bag ....

....gives equivalence rules between terms in the collection algebra. The rules aim to highlight properties of the non conventional operations in the collection algebra. To use the rules in a real optimiser many other transformations are also necessary, some sources for additional transformations are [4,26,38]. Two notions of equivalence are used in the rules given below. For operations returning a collection, equivalence is defined over the elements of the collections as is supported by equal in the collection algebra. For operations returning a value that is not a collection, equivalence is defined ....

S.L. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, University of Wisconson - Madison, U.S.A., 1993.

....structural part of OO database to represent the extended database model. Keywords: database semantics, object oriented databases, database modelling. 1 Introduction In spite of considerable research effort directed to the problems of the formalisation of object oriented (OO) database models [16, 3, 6, 10, 14, 23] in the last decade, there is still a lack of a strong theoretical background for OO databases. The main reason for this lies in the rich set of sophisticated data modelling constructs provided by OO database models [6] In this paper we focus on one aspect of the OO database models: a structural ....

....T and A i 2 A. 2 Let us present an example of a type. The tuple [name:string; age:int; works: organisation; lives at:address] can represent the properties of employee. The type of the attribute age is the primitive type int. Next, the class identifier organisation has the role of a reference type [23]. 3.3 Interpretation Close integration of the concepts of class identifier and type provides a clear method for the definition of type interpretation which can be now defined as a straightforward extension of the class interpretation. The type interpretation is defined as follows. Note that in ....

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S.L. Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, Technical Report #1161, University of Wisconsin-Madison, July 1993

....identifiers is extended to include individual identifiers. A member of a given class identifier is related to this class identifier by the relationship i . Formally, o 2 I c (c) o i c, where o represents an individual identifier and c is a class identifier. The inherited interpretation [2, 24] of a class identifier c, denoted as I c (c) includes all instances of c, that is, the members of c and the members of c 0 s subclass identifiers. Formally, I c (c) S c j i cc j 2Vc I c (c j ) where V c denotes the set of all class identifiers of a given database. 1 The object ....

S.L. Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, Technical Report No. 1161, University of Wisconsin, July 1993.

....object algebra, query languages, complex objects, conceptual schema. 1 Introduction The characteristics of a database algebra have to reflect the properties of the algebraic structures for which algebraic operations are intended. From this perspective, the differences between an object algebra [55, 2, 47, 53, 32, 29, 33, 51] and an algebraic language defined for the manipulation of relations [16, 41, 1] for instance, can be regarded as the consequences of differences in the underlying data models. The features that have to be included in the object algebra are operations for handling the modelling constructs which ....

....of identifiers [42, 45] The ordinary class interpretation maps class identifiers onto sets of individual identifiers called the members of the class. By taking into account the previously defined partial ordering of identifiers, another interpretation is introduced. The inherited interpretation [3, 55] of the class identifier c includes the members of the class c and the members of the subclasses of class c. Let c 2 OC . The inherited interpretation of c, denoted I c (c) is defined as: I c (c) S p2OCp i c I c (p) Using the above definition of the inherited interpretation, we ....

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S.L. Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, Technical Report No. 1161, University of Wisconsin, July 1993.

....the query optimizer which minimizes the data transfer and the computation time involved in processing of queries over distributed data sources. The design of the algebra for the distributed database sources relays on the existing work on the relational and object relational query execution systems [10, 4, 16, 7, 9]. The kernel of the algebra comprises relational operations extended for the manipulation of complex objects. The new constructs are included in the algebra to reflect the specific properties of the data environment. Firstly, the algebra is based on the formal view of object oriented and ....

S.L. Vandenberg, `Algebras for Object-Oriented Query Languages', Ph.D. thesis, Technical Report No. 1161, University of Wisconsin, July 1993.

....certain principles, including inheritance, polymorphism, encapsulation and property overriding [9, 15] While the main features of the object oriented data model are relatively widely accepted [43] the main characteristics of object algebra have not yet been identified. Recently proposed algebras [5, 46, 82, 70, 52, 50, 77, 80, 34] are quite varied in approach and sometimes differ significantly in their basic sets of algebraic operations. This may be due to the different starting points of the algebras, if we suppose that the target al..gebraic structures are fixed i.e. complex objects [9, 15] structured by means of tuple, ....

.... language has certain advantages over declarative languages based on logic e.g. F Logic [41] One of these is the functional nature of the language, which fits with the syntax and semantics of a database programming 3 The function ApplyToAll is also known by the names maplist [33] set apply [82], replace [5] etc. language. However, the same advantage has been claimed to make a language less declarative than query languages based on logic [33] The functional nature of the algebraic query language, together with the ability to compose algebraic operations using a composition operator, ....

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S.L. Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, Technical Report No. 1161, University of Wisconsin

....are defined using the constructs used in our formalisation of the OO data model. Henceforth, the operations are referred to as model based operations. Use of the proposed model based operations in declarative queries expressed by the operations frequently defined in recent object algebras [19, 1, 18, 13, 16] is presented. For this purpose, the set of operations, which are closely related to the operations of Query Algebra proposed by Shaw and Zdonik in [18] is defined in the paper. The following two types of query that use the conceptual schema are studied: i) queries that are used for inquiring ....

....[16] is presented. Related work is overviewed in Section 7. Finally, concluding remarks are given in Section 8. 2 Data Model In this section, we present the formalisation of an object oriented data model Oval [16] The data model provides, in addition to the basic constructs of OO data models [3, 6, 19], a uniform view of the database by treating classes as abstract objects. In this respect, the formalisation of the presented OO data model is based on ideas introduced in the logic based declarative language F Logic [11] Objects and Classes An object is defined as a couple i; v , where i is ....

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S.L. Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, University of Wisconsin,

....user should be able to query the relationships between the instances and the conceptual schema of a database. Secondly, due to the frequently very complex conceptual schema, a user should be able to query it in order to obtain a precise mental image of the structure and the behavior of stored information [ 10 ] In this paper we present the operations of the algebra for objects called OVAL, which are used for querying conceptual schema. The following section briefly overviews the work related to OVAL. Next, the basic constructs used for the formalization of the OVAL s data model are defined in ....

....in Section 4. Finally, the concluding remarks are given in Section 5. 2 Related work The constructs that recent query languages provide for querying database schema are briefly presented in this section. To our knowledge, recently proposed database algebras (e.g. Query algebra [ 13 ] Excess [ 14 ] or Complex Object Algebra [ 1 ] do not include such facilities. Firstly, most recent query languages (e.g. query languages of ORION [ 9 ] or O 2 DBMS [ 4 ] provide the constructs for using the class extensions [ 5 ] in queries. In [ 5 ] Bertino proposes the use of operator CLASS OF , which ....

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S.L.Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, Technical Report No. 1161, University of Wisconsin,

.... A number of proposals for object oriented query languages include arrays, see [22, 9] The ODMG proposal includes one dimensional arrays with a limited set of supported operations [8] Vandenberg and DeWitt propose an object oriented algebra supporting arrays in addition to other constructs [31, 30]. They only treat one dimensional arrays. The array operations in [31, 30] are very similar to typical list operations, but also include operations for array subscripting. Organization. In section 2 we describe the design of a nested relational calculus for arrays, NRCA. This calculus forms the ....

....see [22, 9] The ODMG proposal includes one dimensional arrays with a limited set of supported operations [8] Vandenberg and DeWitt propose an object oriented algebra supporting arrays in addition to other constructs [31, 30] They only treat one dimensional arrays. The array operations in [31, 30] are very similar to typical list operations, but also include operations for array subscripting. Organization. In section 2 we describe the design of a nested relational calculus for arrays, NRCA. This calculus forms the theoretical basis for our array query language AQL in much the same way ....

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S. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, Univ. of Wisconsin, 1993.

....operations for creating, inserting, updating, subscripting and resizing. Their arrays seem to support in place updates, since they can have holes and there is an explicit resize operation. Vandenberg and DeWitt propose an objectoriented algebra supporting arrays in addition to other constructs [31, 32]. They only treat one dimensional arrays. The array operations in [31, 32] are very similar to typical list operations, but also include operations for array subscripting. Organization. In section 2 we describe the design of a nested relational calculus for arrays, NRCA. This calculus forms the ....

....Their arrays seem to support in place updates, since they can have holes and there is an explicit resize operation. Vandenberg and DeWitt propose an objectoriented algebra supporting arrays in addition to other constructs [31, 32] They only treat one dimensional arrays. The array operations in [31, 32] are very similar to typical list operations, but also include operations for array subscripting. Organization. In section 2 we describe the design of a nested relational calculus for arrays, NRCA. This calculus forms the theoretical basis for our array query language AQL in much the same way ....

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S. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, Univ. of Wisconsin, 1993.

....ability to look at large portions of the trees (since the query rep is a tree) and the patterns which describe when a rule matches need to be able to take into account more of the surrounding context of the tree. As part of the EREQ project, a query language for trees and lists has been developed [84, 89]. Our rule language adapts and extends that work, allowing us to use the query language to specify pattern matches in the tree representation of queries, and also allows us to use queries in computing the actions to be taken when a rule is to fire. The tree query language consists of a set of ....

Scott L. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, Computer Sciences Department, University of Wisconsin-Madison, Madison, WI 53706, June 1993.

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S. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, Univ. of Wisconsin, 1993.

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S. Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, Computer Sciences Department, University of Wisconsin-Madison, Madison, WI 53706, June 1993.

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Scott L. Vandenberg. Algebras for Object-Oriented Query Languages. Technical Report CS-TR-1993-1161, University of Wisconsin-Madison, 1993.

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Scott L. Vandenberg. Algebras for Object-Oriented Query Languages. Technical Report CS-TR-1993-1161, University of Wisconsin-Madison, 1993.

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S.L. Vandenberg, Algebras for Object-Oriented Query Languages, Ph.D. thesis, Technical Report No. 1161, University of Wisconsin, July 1993.

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S.L. Vandenberg, `Algebras for Object-Oriented Query Languages', Ph.D. thesis, Technical Report No. 1161, University of Wisconsin, July 1993.

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Scott Lee Vandenberg. Algebras for Object-Oriented Query Languages. PhD thesis, University of Wisconsin-Madison, 1993.

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