Proper handling of query results towards maximizing reusability in object-oriented databases

Alhajj, Reda; Polat, Faruk

doi:10.1016/s0020-0255(97)10051-2

Cited by 11 publications

(6 citation statements)

References 7 publications

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“…We use = and := to differentiate between temporary and persistent based evaluations, respectively. While a temporary based evaluation of a query ends by finding the triplet of sets in the answer, a persistent based evaluation continues with the finding of additional class characteristics of the determined triplet (Alhajj and Polat, 1998;Alhajj and Polat, 1994).…”

Section: P Expression (R)=[]mentioning

confidence: 99%

Simplifying the Formulation of a Wide Range of Object-Oriented Complex Queries

Alhajj

2000

Journal of Database Management

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We present a model that simplifies the formulation of a wide range of complex, mainly selection-based, object-oriented queries, including linear recursive queries. They are complex because it is almost impossible for naive users to predict the formulation of their predicate expressions. Naive users are mainly decision makers who are most probably not computer professionals. Therefore, it is necessary to provide them with a straightforward and easy-to-handle approach to retrieve the information required for the decision making process. To achieve this, the definition of the selection operation and the predicate definition are adjusted to make it possible to have in the output only a subset of the objects from the actual result of a linear recursive query. Otherwise, it is infeasible to achieve the same output without an additional selection with a complicated predicate. We also define an operation that facilitates applying aggregate functions on objects. The two operations proved to be very useful and necessary to study the characteristics of trees and directed graphs. The presented model has been implemented as a part of our object-oriented database management system prototype.

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Section: P Expression (R)=[]mentioning

confidence: 99%

Simplifying the Formulation of a Wide Range of Object-Oriented Complex Queries

Alhajj

2000

Journal of Database Management

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“…This way, closure is maintained within the model where a view can be smoothly used as an operand. We dealt with stored queries in our query model described in [5,7,9], and managed to handle the proper placement of a query result in the hierarchy. For instance, the result of project is a superclass of the class of the operand, the result of join is a subclass of the classes of both operands, while the result of select is a brother class of the class of the operand.…”

Section: I1mentioning

confidence: 99%

“…Furthermore, it focuses on the specification of a consistent view schema graph rather than an individual view class. Our approach described in [5,7,8,9] is a step in this direction where we handle the proper placement of a query result in order to maintain closure and maximize reusability.…”

Section: Related Workmentioning

confidence: 99%

“…The Po parts of the definitions of these classes are shown in Fig. 4 As is obvious from the examples and detailed more in [7,8,9], virtual classes serve to hold query results. Their introduction do help in reusability maximization as they share the same class definitions with certain base classes.…”

Section: Illustrating Examplesmentioning

confidence: 99%

“…Actually, NEC and COR classes were introduced as a pan of the Object-Oriented Database Management System developed at Bilkent University [5,6,7,8,9,10,17,35]. Explicitly, NEC holds all class-to-class relationships along the class-composition hierarchy, i.e., a relationship between two classes c~ and ~ is included in NEC to show that class c~ has an attribute the value of which is drawn from W,,, ..... (Cj).…”

Section: Io(cor) = {Findreferenceingobjects(targetclass)}mentioning

confidence: 99%

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Incremental materialization of object-oriented views

Alhajj

Elnagar

1999

Data & Knowledge Engineering

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We present an approach to handle incremental materialization of object-oriented views. Queries that define views are implemented as methods that are invoked to compute corresponding views. To avoid computation from scratch each time a view is accessed, we introduce some deferred update algorithms that reflect for a view only related modifications introduced into the database while that view was inactive. A view is updated by considering modifications performed within all classes along the inheritance and class-composition subhierarchies rooted at every class used in deriving that view. To each class, we add a modification list to keep one modification tuple per view dependent on that class. Such a tuple acts as a reference point that marks the start of the next update to the corresponding view.

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Documenting Legacy Relational Databases

Alhajj

1999

Lecture Notes in Computer Science

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Proper handling of query results towards maximizing reusability in object-oriented databases

Cited by 11 publications

References 7 publications

Simplifying the Formulation of a Wide Range of Object-Oriented Complex Queries

Simplifying the Formulation of a Wide Range of Object-Oriented Complex Queries

Incremental materialization of object-oriented views

Documenting Legacy Relational Databases

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