Generating relational database transactions from eb 3 attribute definitions

eb ³ is a trace-based formal language created for the specification of information systems. In eb ³, each entity and association attribute is independently defined by a recursive function on the valid traces of external events. This paper describes an algorithm that generates, for each external event, a transaction that updates the value of affected attributes in their relational database representation. The benefits are twofold: eb ³ attribute specifications are automatically translated into executable programs, eliminating system design and implementation steps; the construction of information systems is streamlined, because eb ³ specifications are simpler and shorter to write than corresponding traditional specifications, design and implementations. In particular, the paper shows that simple eb ³ constructs can replace complex SQL queries which are typically difficult to write.

Integrating relational and object-oriented database systems using a metaclass concept

This paper presents a specific approach of integrating a relational database system into a federated database system. The underlying database integration process consist of three steps: first, the external database systems have to be connected to the integrated database system environment and the external data models have to be mapped into a canonical data model. This step is often called syntactic transformation including structural enrichment and leads to component schemas for each external DBMS. Second, the resulting schemas from the first step are used to construct export schemas which are then integrated into global, individual schemas or views in the third step. In this paper we focus on the first step for relational databases, i.e., the connection of a relational database system and the mapping of the relational model into a canonical data model. We take POSTGRES as the relational database system and the object-oriented federated database system VODAK as the integration platform which provides the open, object-oriented data model as the canonical data model for the integration. We show different variations of mapping the relational model. By exploiting the metaclass concept provided by VML, the modelling language of VODAK, we show how to tailor VML such that the canonical data model meets the requirements of integrating POSTGRES into the global database system VODAK in an efficient way.     

Atomic delegation: object-oriented transactions

Atomic delegation, an object-oriented linguistic mechanism that allows the creation of dynamically defined classes of atomic actions is presented. When a type is modified, atomic delegation updates functionalities of the the types that delegate to the modified type. This mechanism permits dynamic binding and code reuse in atomic actions. The Sina language is used to illustrate the utility of atomic delegation in the modeling of a real-world problem, involving an office with a number of departments, using object-oriented techniques. Implementation issues are discussed     

Decomposition of object-oriented database schemas

We specify a data model with object-oriented and logic-oriented features. The model is based on F-logic. For this model, we study a decomposition of a class, the counterpart to the well-known decomposition of a relation scheme under functional dependencies. For this decomposition of a class, the transformation pivoting is used. Pivoting transplants some attributes of the class to a newly generated class. This new class is a subclass of the result class of the so-called pivot attribute. The pivot attribute maintains the link between the original class and the new subclass. We identify the conditions under which input and output of pivoting are equivalent. Additionally, we show under which conditions a schema with functional dependencies can be recursively transformed into an equivalent one without non-key functional dependencies.     

An interface between object-oriented databases and relational databases

Currently relational databases are widely used, while object-oriented databases are emerging as a new generation of database technology. This paper presents a methodology to provide effective sharing of information in object-oriented databases and relational databases. The object-oriented data model is selected as a common data model to build an integrated view of the diverse databases. An object-oriented query language is used as a standard query language. A method is developed to transform a relational data definition to an equivalent object-oriented data definition and to integrate local data definitions. Two distributed query processing methods are derived. One is for general queries and the other for a special class of restricted queries. Using the methods developed, it is possible to access distributed object-oriented databases and relational databases such that the locations and the structural differences of the databases are transparent to users.     

Index organizations for object-oriented database systems

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 is 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     

Towards a deductive object-oriented database language

A language for databases with sets, tuples, lists, object identity and structural inheritance is proposed. The core language is logic-based with a fixpoint semantics. Methods with overloading and methods evaluated externally providing extensibility of the language are considered. Other important issues such as updates and the introduction of explicit control are discussed.     

Translating networked learning: un-tying relational ties

Abstract   This article explores the social network of learning beyond a functional understanding of social relations. It describes and interprets the realities of networked learning within a particular postgraduate course in an English university setting. It draws attention to some of the limitations of the increasing interest in the use of social network analysis (SNA) alongside content analysis of recent studies in the field of networked learning. In particular, SNA has been used to analyse response relations among participants in online discussions in terms of, for example, density and centrality. It argues for a different approach to a network of learning, focusing on the relational effects of multiple technical and social arrangements and engagements beyond the response relations the online environment is able to capture and store. This approach emphasizes network processes rather than network structures.     

Beyond the relational database model

The relational model is a set-theoretic model for describing data constructs common in the business environment. Relational databases also minimize data duplication, which ensures data integrity and reduces storage requirements. Further, the relational model provides a way to represent variable-length constructs with fixed-length components. In addition, normalization theory is the basis of hundreds of papers and successful tenure applications. This ensured the academic community would carry the model forward. Finally, by following open standards, including the structured query language, vendors created a buzz with dozens of relational DBMS products such as System R, DB2, Oracle, SQL Server, Ingres, dBase, R:Base, Pearl, Paradox, and Access. An XDS have many advantages over a relational database, including seamless integration with user views as well as all the benefits of XML standards such as XML schema validation and the extensible stylesheet language for document materialization.     

An object-oriented product database using ROSE

A product database for a design and manufacturing enterprise serves as a repository for the data needed to manufacture a product. This paper discusses how an object-oriented persistent object manager named ROSE, under development at Rensselaer, has been used in the Rensselaer CIM program to develop a STEP/PDES-compliant product database for its research test bed. In so doing, it provides an overview of the requirements for a product database system in an integrated design and manufacturing facility, and it discusses how the chosen system meets these requirements.     

Hierarchical to relational database migration

Although database migration has not yet been extensively researched, three predominant software solutions have evolved: language interfaces, source-code conversion, and data propagation. The authors consider how Swiss Bank and IBM designed and developed the IBM Data Propagator MVS/ESA, which supports interactive and batch data propagation. This software migrates data from the hierarchical IMS to the relational DB2, without affecting existing applications. It supports forward and reverse data propagation, which lets heterogeneous databases coexist. At Swiss Bank, the Data Propagator MVS/ESA handles the main customer and account databases at all five computer centers in Switzerland     

Translating relational schema into XML schema definition with data semantic preservation and XSD graph

Many legacy systems have been created by using relational database operating not for the Internet expression. Since the relational database is not an efficient way for data explosion, electronic transfer of data, and electronic business on the Web, we introduce a methodology in which a relational schema will be translated to an Extensible Markup Language (XML) schema definition for creating an XML database that is a simple and efficient format on the Web. We apply the Indirect Schema Translation Method that is a semantic-based methodology in this project. The mechanism is that the Relational Schema will be translated into the conceptual model, an Extended Entity Relationship (EER) Model using Reverse Engineering. Afterward, the EER model will be mapped to an XML Schema Definition Language (XSD) Graph as an XML conceptual schema using Semantic Transformation. Finally, the XSD Graph will be mapped into the XSD as an XML logical schema in the process of Forward Engineering, and the data semantics of participation, cardinality, generalization, aggregation, categorization, N-ary and U-ary relationship are preserved in the translated XML schema definition.     

Finding hydrophobic microdomains using an object-oriented database

A procedure for finding clusters of adjacent residues in protein hydrophobic cores--hydrophobic microdomains--has been proposed by Plochocka et al. A program is presented that finds hydrophobic microdomains, making use of protein structure data stored in an object-oriented database and the list-processing features of Prolog. Alternative definitions for hydrophobic microdomains are explored. Results are presented for haemoglobin.     

Formalization of object-oriented database model with rules

The paper investigates knowledge representation in an object-oriented database management system first within the data model with rules and second in the computational model by using logic. Issues of structure, integrity, and retrieval are focused on. The proposed system provides object-oriented concepts for describing complex structured data, rules for expressing object-dependent constraints and object associations, and, finally, logic for inference and retrieval.     

Numerical operations on a relational database

The problem is discussed of defining numerical operations on a relational database to accommodate the statistical analyses associated with a bivariate frequency table. An attempt has been made to extend Codd's relational algebra to include simple bivariate statistical operations preserving the closure of Codd's algebra. This extended algebra is applied to bivariate relational data structures needed for real-time automatic statistical quality control of a manufacturing process. Also discussed are some new category-numeric operations on relational tables     

一种新的关系数据库水印算法研究

针对现有水印算法的不足,提出了一种新的关系数据库水印算法.算法首先筛选出可以嵌入水印信息的属性并将他们划分为若干个等大的子集,然后将水印信息的每个二进制位嵌入到相应的子集中.水印检测依据的是中心极限定理,并且实现了水印信息的准确检测.最后通过SQL server进行仿真实验,验证此方法在现实应用中的有效性.     

可扩展的云关系型数据库的研究

为解决用户使用目前的云数据库服务时他们必须对应用做大量的修改的这种问题,在分析和研究现有的云数据库服务的基础上,提出了一种新型的云关系型数据库平台,它支持多语言开发的SDK机制,同时对数据的垂直、水平分布机制和算法进行了描述.描述了云关系型数据库的可靠性,包括数据存储管理和各种保护机制.仿真性能测试结果表明,在大海量数据量下,该云关系型数据库具有很好的可靠性、可扩展性和易用性.     

类-关系数据库之间的映射

面向对象的开发方法是目前软件开发的主要方法,它以类作为软件分析,设计和实现的基本单元,而关系数据库则是许多人都青睐的持久信息存储方法,所以类－－关系数据库之间的映射是开发者必须关注的一件大事,文章扼要地介绍了类－－关系数据库之间的映射原则。     

AESOP: an architectural relational database

This paper describes the principles and implementation of AESOP, an architectural relational database which aims to integrate building design procedures and to provide good graphic manipulation facilities. It is also intended to be highly flexible in that it allows inexact as well as exact data, can support a variety of user views of data and modes of use, and can accommodate itself to new techniques as these become available. AESOP uses ‘fuzzy’ logic. It holds information in the form of components which are linked lists of records, or relations, which are linked lists of tuples containing pointers to records, or, more generally, as directed graphs with records at the boundaries. New relations can be defined interactively from old using set theoretic operations thus enabling the logical operations of the first order predicate calculus to be performed on relations. The database also holds internal procedures called maps. Maps may be used to transform data as required by the user or to test the properties of a design proposal. New maps can be defined interactively from existing maps by applying composition, recursion or the logical operations of the first order calculus. An example of the use of the principles of fuzzy logic for guiding the selection of building fabri? is given. Some tests of AESOP in practice on live problems are noted. It is concluded that AESOP could provide a useful framework for a CAAD system and that further work is required in two areas, the user interface, and operations involving geometrical relations.