关系数据库数字水印技术

随着知识产权保护和信息安全技术的发展,关系数据库数据存在所有权问题,可以采用数字水印技术对其进行数字所有权管理。该文分析了关系数据库中的数据和图像、声频、视频等多媒体数据的区别及关系数据库水印的特点,探讨了几种关系数据库数字水印技术,还分析了对关系数据库数据水印技术的攻击方式和理想的关系数据库水印技术。水印关系数据库对数据库的安全有着广阔前景和实际应用价值。     

一种基于关系数据库的脆弱性水印算法

为了检测对关系数据库的恶意篡改,提出了一种脆弱性数字水印算法,该算法将数据库的元组划分到不同的分组中,在对分组内的所有元组进行秘密排序的基础上,生成由属性水印和元组水印构成的分组水印矩阵,从而可以将对数据库的篡改定位在分组范围内.理论分析和实验结果表明了该方法的有效性和可行性.     

A Novel Watermarking Scheme for Secure Relational Databases

ABSTRACT

Digital watermarking for relational databases emerged as a candidate solution to provide copyright protection and tamper detection and to maintain the integrity of data. Sectors such as defense, finance, and human resources require reliable schemes, especially for data alteration and integrity checking. Many watermarking techniques have been proposed in the literature to address the above-mentioned problems subject to their limitations on numeric attributes. However, these techniques do not yield satisfactory results in the case of small numeric values. To overcome these limitations, we have proposed a watermarking scheme in which the third most significant bit of numeric and nonnumeric attributes is replaced with the watermark bit without loss of originality. The proposed scheme must be suitable for the above-mentioned sectors, including commercial banks where fraud and forgery cases are common.     

(对象)关系数据库中XML文档的存储技术

XML逐渐成为Web上数据表示和数据交换的标准,随着Web上大量的数据用XML文档表示出来,有必要对这些XML文档进行存储和查询。目前大多数商业数据库产品都支持对XML文档的存储、查询、索引等操作,本文讨论了在ORDB中存储XML文档时所涉及的存储技术,比较了三大商业数据库产品（IBM DB2,Oracle9i,Microsoft SQL Server 2000)在存储XML文档时所采用的方法。     

一种利用模糊关系数据库构建模糊OWL本体的方法

经典OWL本体不能直接表示和处理语义Web应用中广泛存在的模糊知识,鉴于模糊关系数据库在模糊数据表示与处理方面的优势,提出利用模糊关系数据库来构建模糊OWL本体.通过对RDF数据类型进行模糊扩展,并从模糊数据类型角度扩展OWL,解决了模糊OWL本体的表示问题;在此基础上,研究了以模糊关系数据库为数据源的模糊OWL本体的构建方法,该方法为语义Web中模糊本体的构建提供了一个有效的解决方案.     

一种基于RDBMS的XML数据的存储方法

XML作为一种数据交换的标准在互联网上推出,使得XML数据和数据库的相互交换成为必要:一是因为WEB中大量的多样化数据需要进行有效的存储和管理;二是因为在现有的数据库中存储有大量的数据并且需要将这些数据转换为XML发布到WEB中。论文提出了一个基于关系数据库的数据转换框架,基于数据的完整性讨论XML数据存储策略。建立一个XML通用数据模型,把文档树分解成多个节点,根据一定的映射规则存储到关系表中,从而不用考虑文档的模式信息(DTD、XMLSchema)。最后通过一个具体的文档实例来说明这种策略的有效性。     

Multimedia Digital Rights Protection Using Watermarking Techniques

ABSTRACT

With the advancement of Internet technologies and its wide usage, it has become easy to illegally copy, distribute, and manipulate digital products. Digital watermarking is a proven method to protect authenticity by identifying the owner of the digital content. Significant work has been reported in the last five years on legal and technical measures for protecting digital rights. This paper explains the concepts of ownership rights and related intellectual property rights and their technical and legal protection measures. It also introduces digital water marking, its classification, features, and applications.     

Test-Driven Development of Relational Databases

In test-first development, developers formulate and implement a detailed design iteratively, one test at a time. Test-driven development (also called test-driven design) combines TFD with refactoring, wherein developers make small changes (refactorings) to improve code design without changing the code's semantics. When developers decide to use TDD to implement a new feature, they must first ask whether the current design is the easiest possible design to enable the feature's addition. Implementing test-driven database design involves database refactoring, regression testing, and continuous integration. TDDD is an integrated part of the overall development process, not a standalone activity that data professionals perform in parallel with application TDD. Although from a technical view point, TDDD is relatively straightforward, we must overcome several challenges to its whole sale adoption throughout the IT community     

Object-Oriented Databases with Relational DBMSs

The expediency of the use of object-oriented models of data as datalogical models in designing databases is shown, and methods of integration of relational and object-oriented models are considered. A relational scheme for storage of attributes and relations of object-oriented models is proposed.     

Graph Transformation in Relational Databases

We present a novel approach to implement a graph transformation engine based on standard relational database management systems (RDBMSs). The essence of the approach is to create database views for each rules and to handle pattern matching by inner join operations while negative application conditions by left outer join operations. Furthermore, the model manipulation prescribed by the application of a graph transformation rule is also implemented using elementary data manipulation statements (such as insert, delete, update).     

Multidimensional Index Structures in Relational Databases

Efficient query processing is one of the basic needs for data mining algorithms. Clustering algorithms, association rule mining algorithms and OLAP tools all rely on efficient query processors being able to deal with high-dimensional data. Inside such a query processor, multidimensional index structures are used as a basic technique. As the implementation of such an index structure is a difficult and time-consuming task, we propose a new approach to implement an index structure on top of a commercial relational database system. In particular, we map the index structure to a relational database design and simulate the behavior of the index structure using triggers and stored procedures. This can be easily done for a very large class of multidimensional index structures. To demonstrate the feasibility and efficiency, we implemented an X-tree on top of Oracle8. We ran several experiments on large databases and recorded a performance improvement up to a factor of 11.5 compared to a sequential scan of the database.     

Null Inclusion Dependencies in Relational Databases

Functional dependencies (FDs) and inclusion dependencies (INDs) are the most fundamental integrity constraints that arise in practice in relational databases. We introduce null inclusion dependencies (NINDs) to cater for the situation when a database is incomplete and contains null values. We show that the implication problem for NINDs is the same as that for INDs. We then present a sound and complete axiom system for null functional dependencies (NFDs) and NINDs, and prove that the implication problem for NFDs and NINDs is decidable and EXPTIME-complete. By contrast, when no nulls are allowed, this implication problem is undecidable. This undecidability result has motivated several researchers to restrict their attention to FDs and noncircular INDs in which case the implication problem was shown to be EXPTIME- complete. Our results imply that when considering nulls in relational database design we need not assume that NINDs are noncircular.     

Table Oriented Metrics for Relational Databases

Developing and selecting high quality software applications are fundamental. It is important that the software applications can be evaluated for every relevant quality characteristic using validated metrics. Software engineers have been putting forward hundreds of quality metrics for software programs, disregarding databases. However, software data aspects are important because the size of data and their system nature contribute to many aspects of a systems quality. In this paper, we proposed some internal metrics to measure relational databases which influence its complexity. Considering the main characteristics of a relational table, we can propose the number of attributes (NA) of a table, the depth of the referential tree (DRT) of a table, and the referential degree (RD) of a table. These measures are characterized using measurement theory, particularly the formal framework proposed by Zuse. As many important issues faced by the software engineering community can only be addressed by experimentation, an experiment has been carried out in order to validate these metrics.     

XML文档在关系数据库中的规范化存储

提出了一种存储方法，首先把XML文档映射为泛关系模式，再利用算法DeriveFDs推导出XML键所蕴含的泛关系模式上函数依赖集的规范覆盖，根据此规范覆盖，最后将泛关系模式保持函数依赖地分解为3NF模式集。得到了保持XML键约束的规范化存储模式，实现了XML文档在关系数据库中的规范化存储。实验研究表明文中提出的方法是有效的。     

On Normalization of Relations in Relational Databases

A new normal form, namely, object-normal form (ONF), is introduced. It is shown that the existing definitions of the fifth normal form (5NF) are unsatisfactory. The correct definition is given for the first time. The importance of the 5NF is demonstrated. For improving data representation in a database with a 5NF schema, the notion of negating relation is introduced. It serves as a basis for the new normal form, namely, the sixth normal form. Combining requirements of the ONF and other normal forms, new normal forms are defined: the fourth object-normal form, the fifth object-normal form, and the sixth object-normal form. It is shown that the standard order of steps of the normalization procedure should be changed: first, the specific requirements of the fourth normal form should be satisfied, and only then the requirements of the second normal form, and so forth.     

Bottom-Up Association Rule Mining in Relational Databases

Although knowledge discovery from large relational databases has gained popularity and its significance is well recognized, the prohibitive nature of the cost associated with extracting such knowledge, as well as the lack of suitable declarative query language support act as limiting factors. Surprisingly, little or no relational technology has yet been significantly exploited in data mining even though data often reside in relational tables. Consequently, no relational optimization has yet been possible for data mining. We exploit the transitive nature of large item sets and the so called anti-monotonicity property of support thresholds of large item sets to develop a natural least fixpoint operator for set oriented data mining from relational databases. The operator proposed has several advantages including optimization opportunities, and traditional candidate set free large item set generation. We present an SQL3 expression for association rule mining and discuss its mapping to the least fixpoint operator developed in this paper.     

一种新的关系数据库水印方法

目前关系数据的权利保护问题已引起人们广泛的关注,对数据库嵌入水印是一种有效的解决办法。该文提出了一种新的数据库水印方法,分析了该方法对各种主要攻击,如元组重新排序、子集选择、属性删除等的抵抗能力。最后该文实现了这种水印方法并给出了实验数据,证明了该算法具有很强的鲁棒性。     

层次数据上关键字检索的结果聚合

由于使用方便等优点,数据库上的关键字检索技术使用户可以得到所需信息而不必书写复杂的SQL语句.但大部分现有的检索方法都关注通过连接操作得到包含所有关键字的元组连接树,忽略了对于检索结果的信息整合,这从某种程度上影响了用户对于检索结果的判断.文中提出并实现一种改进的关键字检索系统框架,在具有层次结构的属性指导下对得到的元...     

关系数据库排名运算方法的研究

排名运算按次序为数据库查询结果集中的每行分配一个排名值,针对RDBMS上无法直接支持排名运算的状况,提出了多种解决方案,通过在基准测试下分析各方案的性能差异,给出不同情况下的最佳方案。     

基于关系数据库的模糊查询技术

在关系数据库中,SQL只能处理精确查询,而现实中存在许多模糊查询的问题。在模糊逻辑理论的基础上,提出了关系数据库的模糊查询思路,并详细地讨论了在数值和字符属性上的实现方法。实现方法不仅对数据库的查询进行了扩展,而且对实际系统的开发也有一定的借鉴作用。