The generation of execution plans for object-oriented database queries is a new and challenging area of study, Unlike the relational algebra, a common set of object algebra operators has not been defined, Similarly, a...
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The generation of execution plans for object-oriented database queries is a new and challenging area of study, Unlike the relational algebra, a common set of object algebra operators has not been defined, Similarly, a standardized object manager interface analogous to storage manager interfaces of relational subsystems does not exist. We define the interface to an object manager whose operations are the executable elements of query execution plans, Parameters to the object manager interface are streams of tuples of object identifiers. The object manager can apply methods and simple predicates to the objects identified in a tuple. Two algorithms for generating such execution plans for queries expressed in an object algebra are presented. The first algorithm runs quickly but may produce inefficient plans, The second algorithm enumerates all possible execution plans and presents them in an efficient, compact representation.
In this study, we focus on the stability and behavior of three widely used clustering algorithms. Various correlation coefficients are computed to help us understand the sensitivity of object clustering. Surprisingly,...
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In this study, we focus on the stability and behavior of three widely used clustering algorithms. Various correlation coefficients are computed to help us understand the sensitivity of object clustering. Surprisingly, the results indicate that there is almost no difference among any clustering approach. Furthermore, all methods appear to be near stable. These findings tend to show that the clustering algorithms are independent of the way objects are inherently clustered.
In this paper we present an indexing technique providing support for queries involving complex, nested objects and inheritance hierarchies. This technique is compared with two techniques obtained from more traditional...
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In this paper we present an indexing technique providing support for queries involving complex, nested objects and inheritance hierarchies. This technique is compared with two techniques obtained from more traditional organizations, The three techniques are evaluated using an analytical cost model. The discussion will be cast in the framework of object-oriented databases, However, results are applicable to data management systems characterized by features such as complex objects and inheritance hierarchies.
The high-level domain-independent query language PICQUERY+ for pictorial and alphanumeric database management is introduced. The PICQUERY+ language and its underlying stacked image data model is enhanced with major ad...
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The high-level domain-independent query language PICQUERY+ for pictorial and alphanumeric database management is introduced. The PICQUERY+ language and its underlying stacked image data model is enhanced with major advances introduced herein including: 1) convenient specification of the data domain space among a multimedia database federation, 2) visualization of underlying data models, knowledge-based hierarchies, and domain rules, 3) understanding of high-level abstract data types, 4) ability to perform data object matches based on imprecise or fuzzy descriptors, imprecise relational correlators, and temporal and object evolutionary events, 5) specification of alphanumeric and image processing algorithms on data, and 6) specification of alphanumeric and image visualization methods for user presentation. The power of PICQUERY+ is presented and illustrated using examples drawn from the medical imaging domain. A graphical menu-driven user interface is demonstrated for this domain as an example of the menu interface capabilities of PICQUERY+.
This paper describes a model for developing applications of active object-oriented databases based on three orthogonal concepts;methods, guards and actions and a tool which implements these ideas called MGA. MGA objec...
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This paper describes a model for developing applications of active object-oriented databases based on three orthogonal concepts;methods, guards and actions and a tool which implements these ideas called MGA. MGA objects are active;they have guards which constrain the object's state, actions which maintain database integrity when the object's state changes, and methods through which the object provides other services. These active components are implemented as (collections of) rules and rules are in turn modelled as objects.
In the last few years, there has been a discernible shift in the system development paradigm from traditional, structured approaches to the object-oriented (OO) paradigm. Several organizations have begun to move towar...
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In the last few years, there has been a discernible shift in the system development paradigm from traditional, structured approaches to the object-oriented (OO) paradigm. Several organizations have begun to move towards distributed systems and OO development in an effort to exploit the benefits of distribution, coupled with the promise of efficient development. It is suggested that successful adoption of distributed object computing, will require careful attention to a number of issues, some of which include deployment and management of distributed OO systems. This article proposes a comprehensive scheme for effective distribution of OO applications over existing networks of computers. The proposed scheme exploits relevant features of OO systems and extends current data distribution research to identify and formalize appropriate design criteria and develop techniques for optimization of these criteria. The scheme consists of two levels. The first specifies procedures and algorithms that can be used to distribute OO systems across geographically dispersed locations. The second level formulates several performance criteria and an iterative decision support procedure. INSET: Facilitating object Distribution.
The objective of the presented approach is to increase productivity of the design process by informing designers about the correlations to parallel work and by practising collaborative work. A cooperative design proce...
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The objective of the presented approach is to increase productivity of the design process by informing designers about the correlations to parallel work and by practising collaborative work. A cooperative design process is support by a shared design database called the Active Semantic Network (ASN). The ASN is an active, distributed, and object-oriented database system that supports the definition of constraints that are evaluated by a rule-based approach. Constraints and locking conflicts are used to find out when the work of designers coincides and they have to adapt their work to results of colleagues. Additional to the support of information exchange, a cooperative transaction model provides several cooperation mechanisms to allow users to exchange partial results and share common data.
We study an object-oriented data model that allows to express both uniqueness constraints and inclusion dependencies as semantic constraints. The data model is based on a subset of F-logic. Uniqueness constraints comp...
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We study an object-oriented data model that allows to express both uniqueness constraints and inclusion dependencies as semantic constraints. The data model is based on a subset of F-logic. Uniqueness constraints comprise path functional dependencies which generalise functional dependencies and reflect the navigational power of object-oriented query languages. As inclusion dependencies, we consider explicit class inclusion constraints, besides inclusions required by class hierarchies, and onto constraints that enforce reachability of objects. For these classes of semantic constraints we present an axiomatisation and prove its inference rules to be correct and complete with respect to general logical implication, leaving the decision problem open. The completeness proof combines the known construction for path functional dependencies alone with a possibly infinite model generation process to enforce onto constraints. The results prepare the grounds for normal forms in object-oriented data models and subsequently for computer aided object-oriented database design, following the decomposition approach for the relational data model. Beyond the application for schema design, the achievements could also be exploited for related tasks like semantic query optimisation and mediated data integration within a variety of graph based data models.
This paper discusses how existing and proposed Database Language SQL and Remote Database Access (RDA) standards can fulfill critical operational requirements for data management. SQL and RDA are but two components of ...
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This paper discusses how existing and proposed Database Language SQL and Remote Database Access (RDA) standards can fulfill critical operational requirements for data management. SQL and RDA are but two components of a family of data management standards needed to meet requirements for emerging distributed processing systems. Requirements for needed capabilities such as object-oriented database, distributed database, and database export/import are discussed.
Even though object-oriented development was introduced in the late 1960s(beginning with the Simula programming language), OO development has not yet lived up to itspromises. A major stumbling block to reaping the prom...
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Even though object-oriented development was introduced in the late 1960s(beginning with the Simula programming language), OO development has not yet lived up to itspromises. A major stumbling block to reaping the promised benefits is learning the OO approach (see[6]). One reason that learning OO is so difficult may be that we do not yet thoroughly understandthe fundamental concepts that define the OO approach. When reviewing the body of work on OOdevelopment, most authors simply suggest a set of concepts that characterize OO, and move on withtheir research or discussion. Thus, they are either taking for granted that the concepts are knownor implicitly acknowledging that a universal set of concepts does not exist. Several authors,asserting there is no clear definition of the essence of OO, have called for the development of aconsensus. While a few have tried to develop such a consensus, to date a thorough review of theliterature and identification of the fundamental concepts of the OO approach has been lacking. Thegoal of this article is twofold: to identify and describe the fundamental concepts, or quarks, ofobject-oriented development, and identify how these concepts fit together into a coherent scheme.
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