241 research outputs found
Accessing network databases via SQL transactions in a multi-model database system
http://archive.org/details/accessingnetwork00walpN
Database Systems - Present and Future
The database systems have nowadays an increasingly important role in the knowledge-based society, in which computers have penetrated all fields of activity and the Internet tends to develop worldwide. In the current informatics context, the development of the applications with databases is the work of the specialists. Using databases, reach a database from various applications, and also some of related concepts, have become accessible to all categories of IT users. This paper aims to summarize the curricular area regarding the fundamental database systems issues, which are necessary in order to train specialists in economic informatics higher education. The database systems integrate and interfere with several informatics technologies and therefore are more difficult to understand and use. Thus, students should know already a set of minimum, mandatory concepts and their practical implementation: computer systems, programming techniques, programming languages, data structures. The article also presents the actual trends in the evolution of the database systems, in the context of economic informatics.database systems - DBS, database management systems – DBMS, database – DB, programming languages, data models, database design, relational database, object-oriented systems, distributed systems, advanced database systems
Heuristic Optimization of Physical Data Bases: Using a Generic and Abstract Design Model
Designing efficient physical data bases is a complex activity, involving the consideration of a large number of factors. Mathematical programming-based optimization models for physical design make many simplifying assumptions; thus, their applicability is limited. In this article, we show that heuristic algorithms can be successfully used in the development of very good, physical data base designs. Two heuristic optimization algorithms are proposed in the contest of a genetic and abstract model for physical design. One algorithm is based on generic principles of heuristic optimization. The other is based on capturing and using problem-specific information in the heuristics. The goodness of the algorithms is demonstrated over a wide range of problems and factor values
Database Management of Vedaranyam Taluk, Nagappattinam District, Tamilnadu using Geographic Information System (GIS)
GIS, known as geographical information system, is the latest tool, a computer system for capturing, storing, checking, integrating, manipulating, analysis in and displacing data related to positions on the Earth’s surface. Typically, a geographical information system or (spatial information system) is used for handling maps of one or another. These might be represented as several different layers each layer holds about a particular kind of feature is linked to a position on the graphically image of a map. With the help of GIS a data base management including data or demography, occupation, education, health, drinking water, power, telecommunication, roads/transportation, banks& commercial institutions, agriculture, sanitation, common property resources ,employment, forestry, industries, marketing facilities, etc.The scope of the work involves 1, data pertaining to geological and geophysical resources, human resources, social and economic infrastructure, etc. should be collected, collected, updated, and retrieval on regular basis, 2, generation of real time, reliable database on natural resources, socio-economic, agro- climatic condition, financial, institutional and environmental data using geo- informatics and 3, data base to cater to the needs of planning sharing information to various user organizations with necessary data analysis, etc and would act as a centralized data base for state govt. department/ institutions/ institutions involved in development planning
Binary Relation Database BIRD: Issues of Representation and Implementation
This thesis presents a study of two issues, integrity and homogeneity of information representation, within the area of databases. Treatments of these issues were studied within the standard and semantic database models, leading to the proposal of a new model, the Binary Relation Database, BIRD. The BIRD model uses the binary relationship as the basis for the representation of all database data and meta-data. The inadequacy of integrity definition faculties within current database technology areelaborated in this thesis and were taken into account in the BIRD system. The effects of inhomogeneity of database data and meta-data in current databases are described and the benefits of the homogeneity of information representation in BIRD demonstrated. BIRD was implemented as a prototype database system; using Modula-2, - the implementation and subsequent evaluation of the system are included in this thesis. A simple user menu driven user interface to BIRD was constructed, - the user may manipulate information at any conceptual level in the system in a homogeneous manner. The user is free to manipulate information from any conceptual level at anytime; - BIRD ensures that the database is returned to a consistent state before the next operation may take place. The new model proposed in this thesis fulfilled its objectives, - suggestions for further and implementation oriented work are presented at the end of the thesis
An Interactive DSS Tool for Physical Database Design
The design of efficient physical databases is a complex activity involving the consideration of a large number of factors. Because of the complexity, mathematical programming approaches seeking to optimize the physical database have to make many simplifying assumptions; therefore, their applicability is limited. Further, the database designer may want to experiment with design preferences and features not considered by the mathematical optimization approaches. In order to effectively design the physical database, this article describes an interactive DSS tool, which aides the database designer in this task. The database design is accomplished in the context of a high-level abstract model which is capable of being implemented in a variety of DBMSs and file systems. Because of this generic nature of the abstract model, the utility of the DSS tool is enhanced. The interactive tool not only lets the designer experiment with his own designs, but also provides several heuristic optimization procedures to enable the generation of many good designs. The heuristic designs may be used for final physical database design as well as for further experimentation. The paper also includes examples of how the physical design selected using the abstract model and the interactive tool may be implemented on several DBMSs and file systems
Viaduct : an interactive, very-high-level data manipulation language for a microcomputer-based database system.
Bibliography: leaves 203-210.A very-high-level data manipulation language for a database system is one in which the user specifies in non-procedural terms the operations that are to be performed on the data stored in the database; the actual method by which the operations are executed does not concern the user. VIADUCT provides such an interface to a microcomputer-based database system known as MDBS. Thus VIADUCT allows a microcomputer user lacking in computer sophistication to interact with, and derive the benefits of, a powerful database management system. Additional security restrictions and integrity constraints usually found only on mainframe database management systems are provided by VIADUCT through the mechanism of a subschema generator
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View mappings for query languages
The problems of current use of query languages are looked at. One chief drawback is the undesirable requirement for end user familiarity with and knowledge of the underlying database structures, in order to retrieve data effectively. The approach adopted towards resolving this is by means of high-level view support, using unit view structures called perceived records. A prime concern of this thesis then, is the study of perceived record mappings from the database.
A set of criteria for categorising and analysing the features of database mappings for end-user views is first developed. In addition, a classification of data structure transformations and data item transformations is also presented. The framework is general and is independent of a specific data model or database management system. Its usefulness is demonstrated by its application to the analysis of view transformations from recursive database structures to high-level, unit view structures. In addition, it serves as a basis for evaluating and comparing the mapping facilities in existing systems.
Possible ways of specifying a suitable data model for the perceived record view concept are described. Following on, two general mapping techniques are discussed. This leads to a proposal for a mapping mechanism that supports the flexible derivation of complex perceived record views that can differ considerably from the source structures. The mechanism uses an intermediary canonical transform model. Description of how the transform model mechansim can be used in practical systems to derive perceived record views, is also presented.
The feasibility of the ideas proposed are tested out by implementing an interactive software system for defining perceived record views. For this, a mapping definition language for perceived record derivation is first designed. The control system sets up the structures of the mapping definition language and prompts the End-User-Administrator to define and specify the mappings for a perceived record. Appraisals of both the proposed mapping mechanism and implementation are discussed. Examples of use of the interface system are included. The limitations of the implementation are pinpointed with suggestions for further improvements. Practical applications of the work and evaluation of the approach in the light of other existing approaches, are also discussed
Restructuring mechanism for a codasyl-type data base
SIGLELD:D48229/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Heuristic Optimization of Physical Databases; Using a Generic & Abstract Design Model
Abstract: Designing efficient physical data bases is a complex activity, involving the consideration of a large number of factors. Mathematical programming-based optimization models for physical design make many simplifying assumptions; thus, their applicability is limited. In this article, we show that heuristic algorithms can be successfully used in the development of very good, physical data base designs. Two heuristic optimization algorithms are proposed in the contest of a genetic and abstract model for physical design. One algorithm is based on generic principles of heuristic optimization. The other is based on capturing and using problemspecific information in the heuristics. The goodness of the algorithms is demonstrated over a wide range of problems and factor values. Subject Areas: Heuristics, Management Information Systems, and Simulation. Article: INTRODUCTION Data base design is a challenging activity and involves two phases: logical and physical design. Logical design involves the development of a logical data structure (LDS) for the task domain. Physical design is concerned with developing structures for placing data on secondary storage, given a specific LDS. While both phases require significant effort, the physical data base design phase is the focus of this article. The main concern in physical data base design is the efficiency of the physical design, which can be measured in a number of ways, such as storage requirement, response time and total system cost. Prior works have generally dealt with and developed design/optimization models for specific aspects of physical data base design. These works include index selection While the attention to individual design problems results in elegant solutions, it is quite plausible that those individual solutions will have to be perturbed when the total data base is put together. [20, p. 217] Thus, the need for comprehensive design models (which deal with the entire data base design problem rather than parts of it) cannot be overstated. Comprehensive physical design models fall under two categories: (1) those specific to and (2) those generic and independent of any particular logical data model and/or commercial DBMS. The first category offers the advantage of direct implementation on a particular DBMS, but is difficult to convert to another implementation. The second category allows more flexibility at the expense of added conversion requirements for a particular implementation. Optimization of physical design in the first category is reported i
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