A unit test approach for database schema evolution

Context

The constant changes in today’s business requirements demand continuous database revisions. Hence, database structures, not unlike software applications, deteriorate during their lifespan and thus require refactoring in order to achieve a longer life span. Although unit tests support changes to application programs and refactoring, there is currently a lack of testing strategies for database schema evolution.

Objective

This work examines the challenges for database schema evolution and explores the possibility of using various testing strategies to assist with schema evolution. Specifically, the work proposes a novel unit test approach for the application code that accesses databases with the objective of proactively evaluating the code against the altered database.

Method

The approach was validated through the implementation of a testing framework in conjunction with a sample application and a relatively simple database schema. Although the database schema in this study was simple, it was nevertheless able to demonstrate the advantages of the proposed approach.

Results

After changes in the database schema, the proposed approach found all SELECT statements as well as the majority of other statements requiring modifications in the application code. Due to its efficiency with SELECT statements, the proposed approach is expected to be more successful with database warehouse applications where SELECT statements are dominant.

Conclusion

The unit test approach that accesses databases has proven to be successful in evaluating the application code against the evolved database. In particular, the approach is simple and straightforward to implement, which makes it easily adoptable in practice.     

面向海量层次信息可视化的嵌套圆鱼眼视图

针对海量层次信息可视化问题,提出嵌套圆鱼眼视图及实现方法.首先分析了相关工作;然后构造了针对同层兄弟节点的变形函数,给出了针对焦点节点同层兄弟节点的外切圆变形排列算法、变形后节点的子节点的嵌套圆递归排列算法及将二维鱼眼视图映射为三维鱼眼视图的方法;最后将该方法应用于计算机文件系统可视化.实验结果表明:该方法在相对小的显示空间内,既能显示海量信息的整体视图,又能突出局部焦点细节信息,具有较高的任务完成效率与用户满意度.     

Search for the Blind : A schema independent query method using concept hierarchy and keywords

Some database schema is very complex and it changes more frequently than the past. On the other hands, in such application database as scientific database and decision-support database, the importance of ad-hoc queries is expected to increase. Therefore the ability of a system to support ad-hoc queries without knowing the database schema information is needed. In this paper, we will describe a method to create candidate structured queries with concept hierarchy using user-input keywords. We will create structured queries in the following step; first, we extract the schema items related to keywords, and second, we compose possible paths between schema items, thus formulate candidate SQL queries.     

Computer aided design of database internal schema

A large number of complexly interrelated parameters are involved at the internal schema level design of database systems. Consequently, a single design model is seen to be infeasible. A package of three aids is proposed to assist a designer in step by step design of internal schema. The three aids pertain to splitting of a relation, merging of relations, and access strategy selection for a relation.     

Knowledge Mining With VxInsight: Discovery Through Interaction

The explosive growth in the availability of information is overwhelming traditional information management systems. Although individual pieces of information have become easy to find, the larger context in which they exist has become harder to track. These contextual questions are ideally suited to visualization since the human visual system is remarkably adept at interpreting large quantities of information, and at detecting patterns and anomalies. The challenge is to present the information in a manner that maximally leverages our visual skills. This paper discusses a set of properties that such a presentation should have, and describes the design and functionality of VxInsight, a visualization tool built to these principles.     

基于《知网》的中文Deep Web模式匹配算法研究

随着数据库在Internet中的应用日益广泛,Deep Web集成（即Web数据库集成）成为当前信息领域的研究热点,模式匹配是Deep Web查询接口集成中的一个关键问题。目前大多数这方面的研究都是基于英文的,针对这种情况,探讨了中文Deep Web查询接口的模式匹配方法,并提出了一种基于《知网》、面向中文语义的模式匹配算法,并利用属性在查询接口上的相对位置信息解决语义冲突。手工收集查询表单对算法进行验证,实验表明该方法能使得接口之间属性匹配的正确率达到90 %以上。     

A visual tool for user-interface development

VITUID is a visual tool for user interface development. It aims to help user-interface designers, who may be non-programmers, to specify and create interactive, graphical user interfaces through graphical interaction. VITUID lets designers specify the user command set and the human-computer dialogs by building a tree and specifying the behavior of each dialog via a dialog-control word, adopting the object-oriented approach. The main strategy of VITUID is to separate a user interface into an application-dependent part and an application-independent part and then let the designer specify only the application-dependent part.     

基于信息导航的三维用户界面动态构建方法

针对三维用户界面对非几何信息表达、交互研究不足的问题,在对界面导航进行研究的基础上,提出了一种基于信息导航的三维用户界面动态构建方法UIDCM。首先,总结了三维界面中的信息导航模型。然后针对导航模型以及复杂信息的表达需求,提出了三维用户界面动态构建方法,并利用此方法实现信息表达、导航交互、命令响应等三维界面功能。最后,利用光学跟踪工具作为三维人机交互手段,搭建了三维用户界面原型系统,并以飞机研制任务信息为实例进行了系统验证。实验表明,UIDCM方法对于三维空间下的信息获取、导航与交互能够提供一种有效的解决方案。     

JAVA和XML Schema在数据有效性验证中的应用

数据的有效性验证是对输入数据正误的判断，分析了几种不同的数据验证方法，提出了新的验证方法即将XML Schema用于JAVA程序的数据有效性验证的可行性，并部分实现这种方案。     

A manufacturing XML schema definition and its application to a data management system on the shop floor

Digitization for sharing knowledge on the shop floor in the machinery industry has been given much attention recently. To help engineers use digitization practically and efficiently, this paper proposes a method based on manufacturing case data that has a direct relation to manufacturing operations. The data are represented in XML schema, as it can be easily applied to Web-based systems on the shop floor. The definitions were made for eight manufacturing methods including machining and welding. The derived definitions consist of four divisions of metadata, work-piece, process and evaluation. Three divisions except for the “process” division are common to the manufacturing methods. The average number of elements for a manufacturing method is about 200. The represented schema is also used to convey knowledge such as operation standards and manufacturing troubleshooting on the shop floor. Using the definitions, a data management system is developed. It is a Web-based Q&A system, in which the engineers specify the manufacturing case data mainly by selecting from the candidates. Then, the system fills in the blank portions and/or shows messages to help complete the case data. The proposed method is evaluated through practical scenarios of arc welding and machining.     

Relational database schema design for uncertain data

Driven by the dominance of the relational model, we investigate how the requirements of applications on the certainty of functional dependencies can improve the outcomes of relational database schema design. For that purpose, we assume that tuples are assigned a degree of possibility with which they occur in a relation, and that functional dependencies are assigned a dual degree of certainty which says to which tuples they apply. A design theory is developed for functional dependencies with degrees of certainty, including efficient axiomatic and algorithmic characterizations of their implication problem. Naturally, the possibility degrees of tuples bring forward different degrees of data redundancy, caused by functional dependencies with the dual degree of certainty. Variants of the classical syntactic Boyce–Codd and Third Normal Forms are established. They are justified semantically in terms of eliminating data redundancy and update anomalies of given degrees, and minimizing data redundancy of given degrees across all dependency-preserving decompositions, respectively. As a practical outcome of our results, designers can simply fix the degree of certainty they target, and then apply classical decomposition and synthesis to the set of functional dependencies whose associated degree of certainty meets the target. Hence, by fixing the certainty degree a designer controls which integrity requirements will be enforced for the application and which data will be processed by the application. The choice of the certainty degree also balances the classical trade-off between query and update efficiency on future database instances. Our experiments confirm the effectiveness of our control parameter, and provide original insight into classical normalization strategies and their implementations.     

A graphical database interface

A graphical database interface suitable for casual, naive users is described. It provides the user with a logical model of the database; this model typically being an abstraction of the actual database structure, and with an easy means of specifying a query through the use of a pointing device. The interface is a front-end processor and is logically separate from the database management system, it is thus possible to use it with any system.     

基于MVC模式的Web用户界面建模

分析了企业信息系统的Web用户界面开发特性,研究了当前主流前端框架的MVC(模型-视图-控制器)设计模式应用,针对Web前端开发需求及最佳实践方法,提出了一种符合MVC用户界面开发最佳实践的组件化Web用户界面建模方法.设计一套抽象和描述Web用户界面组件的UML(统一建模语言)概要文件,从界面数据模型、界面组件模型到界面交互模型等3个方面完成Web用户界面建模.以一个装修行业定制型ERP(企业资源计划)系统为例,通过用户界面建模实践,验证了本建模方法的可行性、易用性和有效性.     

海量层次信息的Focus+Context交互式可视化技术

综述了海量层次信息可视化与Focus Context技术的相关工作,针对海量层次信息可视化的交互问题,在嵌套圆可视化技术的基础上提出了基于上下文感知的Focus Context交互式可视化技术.首先,基于外切圆排列方法提出对圆心进行三角网格剖分的方法,为变形计算建立上下文;然后,针对变形计算前后上下文一致性问题,在三角网格邻居跟踪方法的基础上,提出了用于同层兄弟节点上下文感知的外切圆变形排列方法,以及用于父子节点上下文感知的嵌套圆迭代排列方法.实验结果表明。上述方法在实现焦点突出的鱼眼视图的同时,能够有效地解决Focus Context交互式可视化的上下文感知问题.上述方法应用于文件系统海量层次信息的交互式可视化问题,提供了交互式可视化工具.     

An Interactive Visual Interface for Online Product Catalogs

One of the key elements of e-commerce systems is the online product catalog. It provides sellers with a content management system that assembles, aggregates, normalizes, and distributes product information. It also provides potential buyers with an interactive interface that offers a multimedia representation of the product information as well as retrieval, classification and ordering services. In this paper, we discuss the interface aspect of online product catalogs, focusing on its ability to help shoppers navigate and analyze product information. Specifically, we present a new interactive interface for online product catalogs that effectively enables the shopper to navigate through the product information space and analytically select suitable products.     

Information visualization; assisting low spatial individuals with information access tasks through the use of visual mediators

This study investigated the use of visual mediators to facilitate information access by low spatial individuals. Based on theories of adaptive learning and field-dependence, two human-computer interfaces were developed which were intended to compensate for the inability of low spatial individuals to readily construct visual mental models of a menu system's structure. The two compensatory interfaces included: a 2D visual hierarchy and a linear structure. The information search performance of high and low spatial individuals was compared on the two compensatory interfaces and a third challenge match interface, which challenged individuals to construct a mental model of a hierarchical menu system in order to perform efficiently. The visual mediators were successful in accommodating low spatial individuals, as indicated by the lack of any significant performance differences being detected between the high and low spatial groups on the two compensatory interfaces. High spatial individuals outperformed low spatial individuals only when information search tasks required the use of spatial ability in mentally constructing a model of the organization and structure of embedded task information. The key factor in the accommodation process was the elimination of the need to mentally visualize the structure of embedded task information. These results indicate that visualization techniques can be successfully used to enhance the information search performance of low spatial individuals.