Parallel relational databases have been successful in providing scalable performance for data intensive applications, and much work has been carried out on query processing techniques in such systems. However, althoug...
详细信息
The problem of adding language facilities to express production rule in the framework of a complex object database with active behavior is considered. The issue of the definition of a suitable interaction between prod...
详细信息
When developing large information systems, several forms of data quality checks and controls have to be specified. However, today's objectdatabases only provide very limited support for constraint definition, whi...
详细信息
When developing large information systems, several forms of data quality checks and controls have to be specified. However, today's objectdatabases only provide very limited support for constraint definition, which causes software engineers to implement data quality controls such as consistency checks and exception handling in the application code. Given that it is common for several applications to access the same database, constraints may even be distributed across applications. As a consequence, the same or similar constraints may be checked multiple times in different components of an information system, or even in different applications, which increases code redundancy. Changing constraints may affect multiple parts of the application or even multiple applications. We therefore propose an approach that complements objectdatabases with support for constraint definition, management and validation. We introduce a framework where data quality controls are specified by means of constraints which are defined and managed within the framework and validated against the database based on an event-condition-Action paradigm. Our approach provides flexible and customisable constraint validations, where constraints can either be used to ensure data quality in a strict and traditional way with constraint violations resulting in exceptions, or a relaxed way where constraint violation will generate user warnings and indicate possible deficiencies in data quality. Our framework is extensible and developers are free to introduce new types of constraints. We present our implementation for the object database db4o.
This paper proposes a new approach to model deductive objectdatabases. Each object database is described by means of a Datalog language extended with extensional updates, called U-Datalog. Each object can change its ...
详细信息
A general concern about object-oriented systems has been whether or not they are able to meet the performance demands required to be useful for the development of significant production software systems. Attempts to e...
详细信息
ISBN:
(纸本)0897912845
A general concern about object-oriented systems has been whether or not they are able to meet the performance demands required to be useful for the development of significant production software systems. Attempts to evaluate this assertion have been hampered by a lack of meaningful performance benchmarks that compare database operations across different kinds of databases. In this paper, we utilize the Sun Benchmark [Rube87] as a means for assessing the performance of an object database and comparing it with existing relational systems. We discuss the benchmark, and many of the implementation issues involved in introducing a relationally oriented benchmark into an object-oriented paradigm. We demonstrate the performance of an object database using Ontologic's Vbase object database platform as an example of a commercially available object database, and we compare these benchmark results against those of existing relational database systems. The results offer strong evidence tbat objectdatabases are capable of performing as well as, or better than, existing relational database systems.
Vertical partitioning is a useful technique for performance improvement in parallel and distributed objectoriented database systems (POBSs and DOBSs). Arising from partitioning, there is a need to modify methods in a...
详细信息
ISBN:
(纸本)9783540634409
Vertical partitioning is a useful technique for performance improvement in parallel and distributed objectoriented database systems (POBSs and DOBSs). Arising from partitioning, there is a need to modify methods in a user defined schema for correct execution in the partitioned domain. A partitioning scheme should also support application transparency in order to make schema definitions and vertical partitioning independent. We have followed an approach of method transformations for dealing with these problems. A complete taxonomy for the method types arising from vertical partitioning of a class is presented with transformations for each of these types. The role of the transformations in determining the cost of methods is also briefly presented.
In this paper we describe Kaleidoquery, a visual query language for objectdatabases with the same expressive power as OQL. We will describe the design philosophy behind the filter flow nature of Kaleidoquery and pres...
详细信息
In this paper we describe Kaleidoquery, a visual query language for objectdatabases with the same expressive power as OQL. We will describe the design philosophy behind the filter flow nature of Kaleidoquery and present each of the language's constructs, giving examples and relating them to OQL. The Kaleidoquery language is described independent of any implementation details, but a brief description of a 3D interface currently under construction for Kaleidoquery is presented. The queries in this implementation of die language are translated into OQL and then passed to the object database O2 for evaluation.
Ranking queries have been investigated extensively in the past due to their broad range of applications. In this paper, we study this problem in the context of fuzzy objects that have indeterministic boundaries. Fuzzy...
详细信息
There is a manifold of meanings we could associate with the term "evolution" in the database arena. This paper tries to categorize some of these into a unique framework, showing similarities and differences....
详细信息
There is a lack of cache management in moving objectdatabases which is essentially important for system analysis. In addition, users focus on queries in real scenarios, but cache replacement strategy is not customize...
详细信息
暂无评论