Non-relational database management systems address some of the limitations relational database management systems have when storing large volumes of unstructured, user generated text-based data in distributed environments. They follow different approaches through the data model they use, their ability to scale data storage over distributed servers and the programming interface they provide. An experimental approach was followed to measure the capabilities these alternative database management systems present in their approach to address the limitations of relational databases in terms of their capability to store unstructured text-based data, data warehousing capabilities, ability to scale data storage across distributed servers and the level of programming abstraction they provide. The results of the research highlighted the limitations of relational database management systems. The different database management systems do address certain limitations, but not all. Document-oriented databases provide the best results and successfully address the need to store large volumes of user generated text-based data in a distributed environment / School of Computing / M. Sc. (Computer Science)

Ontology, an explicit specification of a shared conceptualisation, captures knowledge about a specific domain of interest. The realisation of ontologies, revolutionised the way data stored in relational databases is accessed and manipulated through ontology and database integration. When integrating ontologies with relational databases, several choices exist regarding aspects such as database implementation, ontology language features, and mappings. However, it is unclear which aspects are relevant and when they affect specific choices. This imposes difficulties in deciding which choices to make and their implications on ontology and database integration solutions. Within this study, a decision-making tool that guides users when selecting a technology and developing a solution that integrates ontologies with relational databases is developed. A theory analysis is conducted to determine current status of technologies that integrate ontologies with databases. Furthermore, a theoretical study is conducted to determine important features affecting ontology and database integration, ontology language features, and choices that one needs to make given each technology. Based on the building blocks stated above, an artifact-building approach is used to develop the decision-making tool, and this tool is verified through a proof-of-concept to prove the usefulness thereof. Key terms: Ontology, semantics, relational database, ontology and database integration, mapping, Web information portal. / Information Science / M. Sc. (Information Systems)

Regulations and societal expectations have recently emphasized the need to mediate access to valuable databases, even by insiders. At one end of a spectrum is the approach of restricting access to information; at the other is information accountability. The focus of this work is on effecting information accountability of data stored in relational databases. One way to ensure appropriate use and thus end-to-end accountability of such information is through continuous assurance technology, via tamper detection in databases built upon cryptographic hashing. We show how to achieve information accountability by developing and refining the necessary approaches and ideas to support accountability in high-performance databases. These concepts include the design of a reference architecture for information accountability and several of its variants, the development of a sequence of successively more sophisticated forensic analysis algorithms and their forensic cost model, and a systematic formulation of forensic analysis for determining when the tampering occurred and what data were tampered with. We derive a lower bound for the forensic cost and prove that some of the algorithms are optimal under certain circumstances. We introduce a comprehensive taxonomy of the types of possible corruption events, along with an associated forensic analysis protocol that consolidates all extant forensic algorithms and the corresponding type(s) of corruption events they detect. Finally, we show how our information accountability solution can be used for databases residing in the cloud. In order to evaluate our ideas we design and implement an integrated tamper detection and forensic analysis system named DRAGOON. This work shows that information accountability is a viable alternative to information restriction for ensuring the correct storage, use, and maintenance of high-performance relational databases.

Fine-grained access control is a conceptual approach to addressing database security requirements. In relational database management systems, fine-grained access control refers to access restrictions enforced at the row, column, or cell level. While a number of commercial implementations of database fine-grained access control are available, there are presently no generalized approaches to implementing fine-grained access control for relational database management systems. Fine-grained access control is potentially a good solution for database professionals and system architects charged with designing database applications that implement granular security or privacy protection features. However, in the oral tradition of the database community, fine-grained access control is spoken of as imposing significant performance penalties, and is therefore best avoided. Regardless, there are current and emerging social, legal, and economic forces that mandate the need for efficient fine-grained access control in relational database management systems. In the study undertaken, the author was able to quantify the performance costs associated with four common implementations of fine-grained access control for relational database management systems. Security benchmarking was employed as the methodology to quantify performance costs. Synthetic data from the TPC-W benchmark as well as representative data from a real-world application were utilized in the benchmarking process. A simple graph-base performance model for Fine-grained Access Control Evaluation (FACE) was developed from benchmark data collected during the study. The FACE model is intended for use in predicting throughput and response times for relational database management systems that implement fine-grained access control using one of the common fine-grained access control mechanisms - authorization views, the Hippocratic Database, label-based access control, and transparent query rewrite. The author also addresses the issue of scalability for fine-grained access control mechanisms that were evaluated in the study.

A representação e execução de processos de negócio têm gerado importantes desafios na área de Ciência da Computação. Um desses desafios é a escolha do melhor arcabouço formal para a especificação dos controles de fluxo padrões. Algumas linguagens defendem o uso de redes de Petri ou álgebras de processos como base formal. O uso de redes de Petri para especificar workflows clássicos é uma abordagem bastante conhecida. Entretanto, pesquisas recentes vêm difundindo o uso de novas extensões da álgebra de processos como uma alternativa para a especificação formal de workflows. A principal contribuição deste trabalho é a definição da Navigation Plan Definition Language (NPDL). A NPDL foi implementada como uma extensão da linguagem SQL. Ela é uma alternativa para a representação de workflows que utiliza a álgebra de processos como arcabouço formal. A NPDL promove uma separação explícita entre o ambiente de especificação e o ambiente de execução de um workflow. Esta separação propicia o reaproveitamento de passos de negócio e o uso das propriedades da álgebra de processos não só na modelagem, mas também no controle da execução dos processos. Após a especificação de um workflow por meio da NPDL, a execução dos passos que o definem é controlada pela ferramenta NavigationPlanTool. Essa ferramenta é a segunda contribuição deste trabalho de pesquisa. / The representation and execution of business processes have generated some important challenges in Computer Science. An important related concern is the choosing of the best formal foundation to represent control-flow patterns. Some of the workflow languages advocate the Petri nets or process algebra as formal foundation. The use of Petri nets is a famous approach to support classic workflows. On the other hand some researches are introducing modern process algebra extensions as an alternative formal foundation for representing workflows. The first contribution of this research is the definition of the Navigation Plan Definition Language (NPDL). NPDL was implemented as an extension of SQL language. It is an alternative to represent business processes using process algebra as formal foundation. NPDL provides the explicit separation between specification and execution workflow environment. This separation allows reusing of business steps and usage of process algebra properties in the process modeling and execution controlling tasks. After the definition of a workflow using NPDL, the business steps execution is carried out and controlled by a tool called NavigationPlanTool. This tool is the second contribution of this research.

We survey and compare the different major mechanisms for embedding the relational database language SQL in object-oriented programming languages such as Java and C#, with regard to how much impedance mismatch these embeddings suffer. Here impedance mismatch refers to clarity and performance difficulties that arise because of the nature of the embedding. Because of the central position in the information technology industry of object-oriented programs that access SQL-based relational database systems, reducing impedance mismatch is generally recognized in that industry as an important practical problem. We argue for the suitability of SQL as a database language, and hence for the desirability of keeping SQL as the view provided by a SQL embedding. We make the case that SQLJ, a SQL embedding for Java in which it appears that Java directly supports SQL commands, is the kind of SQL embedding that suffers the least impedance mismatch, when compared with call-level interfaces and object-relational mappings. We propose extensions to SQLJ that would reduce its impedance mismatch even further. / by Jose Luis Hurtado. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

XML has emerged as the standard data format for Internet-based business applications. In many bussiness settings, a relational database management system(RDBMS) will serve as the storage manager for data from XML documents. In such a system, once the XML data is shredded and loaded into the storage system, XML queries posed against these (now virtual) XML documents are processed by translating them as much as possible into SQL queries against the underlying relational storage. Clearly, in order to support full database functionalities over XML data, we must allow users not only to query but also to specify updates on XML documents. Today while the XML query language XQuery is being standardized by W3C, no syntax for updating XML documents is included in this language proposal as of now. In this thesis, we have developed techniques for supporting translation of XML updates on XML views of relational data into SQL updates on the underlying relations. These techniques are based on techniques for supporting translation of updates on object-based views of relational data into SQL updates on underlying relations cite{keller91}. The system has been implemented as a part of XML Management System, called Rainbow, that is being developed at the Worcester Polytechnic Institute (WPI). We have used XQuery as XML query language and Oracle as the backend relational store for implementation of the system. Experimental studies show that incremental XML updates supported by our system is a better choice than complete reload of XML documents under a variety of system settings.

Bancos de dados relacionais são fontes de dados rigidamente estruturadas, caracterizadas por relacionamentos complexos entre um conjunto de relações (tabelas). Entender tais relacionamentos é um desafio, porque os usuários precisam considerar múltiplas relações, entender restrições de integridade, interpretar vários atributos, e construir consultas SQL para cada tentativa de exploração. Neste cenário, introduz-se uma metodologia em duas etapas; primeiro utiliza-se um grafo organizado como uma estrutura hierárquica para modelar os relacionamentos do banco de dados, e então, propõe-se uma nova técnica de visualização para exploração relacional. Os resultados demonstram que a proposta torna a exploração de bases de dados significativamente simplificada, pois o usuário pode navegar visualmente pelos dados com pouco ou nenhum conhecimento sobre a estrutura subjacente. Além disso, a navegação visual de dados remove a necessidade de consultas SQL, e de toda complexidade que elas requerem. Acredita-se que esta abordagem possa trazer um paradigma inovador no que tange à compreensão de dados relacionais / Relational databases are rigid-structured data sources characterized by complex relationships among a set of relations (tables). Making sense of such relationships is a challenging problem because users must consider multiple relations, understand their ensemble of integrity constraints, interpret dozens of attributes, and draw complex SQL queries for each desired data exploration. In this scenario, we introduce a twofold methodology; we use a hierarchical graph representation to efficiently model the database relationships and, on top of it, we designed a visualization technique for rapidly relational exploration. Our results demonstrate that the exploration of databases is deeply simplified as the user is able to visually browse the data with little or no knowledge about its structure, dismissing the need of complex SQL queries. We believe our findings will bring a novel paradigm in what concerns relational data comprehension.

O paradigma da orientação a objetos esta se tomando a abordagem preferida para construção de sistemas em ambiente de banco de dados. Por outro lado, a tecnologia relacional e amplamente adotada para gerenciar dados corporativos. Os bancos de dados relacionais tornaram-se o padrão no armazenamento de dados para aplicações de processamento de transações on-line (OLTP). Estas tendências estão motivando a necessidade de construção de aplicações orientadas a objetos que acessem banco de dados relacionais. 0 uso de conceitos orientado a objetos, como herança, permitem uma modelagem !Dais adequada e uma melhor implementação da aplicação baseada em sistema de banco de dados orientado a objetos. Entretanto, os resultados do projeto orientado a objetos, podem também ser aplicados em sistemas clássicos de banco de dados. 0 trabalho apresenta o uso de padrões de projeto na construção de una arquitetura de um framework que auxilie o mapeamento de uma aplicação 00 a um SGBD relacional. Esta arquitetura segue a abordagem de persistência de objetos baseada em gateways, que é uma camada de software inserida entre o sistema gerenciador de banco de dados e a aplicação orientada a objetos, cujo o objetivo é dar suporte a um modelo de programação de aplicações 00. A característica principal desta arquitetura é a separação clara das classes que tratam da base de dados em relação as classes que tratam do domínio do problema da aplicação. Esta divisão de responsabilidades permite a substituição das classes referentes a base de dados por outras, permitindo a migração da aplicação entre bases de dados diferentes. São apresentados neste trabalho, formas de mapeamentos de esquemas orientados a objetos para esquemas relacionais. Estes mapeamentos acontecem do modelo 00 para o modelo relacional. E importante salientar, que a arquitetura que esta sendo proposta, não vai impedir que aplicações estruturadas deixem ter acesso a base de dados relacional mapeada, pois esta abordagem foi escolhida para permitir que novas aplicações 00 tenham acesso a base de dados relacionais já existentes. Como a implementação deste trabalho segue a abordagem de gateway, são apresentados os conceitos de orientação objetos, e como estes serão suportados na arquitetura, ou seja, o que o gateway devera implementar. / The paradigm of the object-oriented is becoming the approach preferred for construction of systems in database environment. On the other hand, the technology relational is adopted thoroughly for management corporate data. The relational databases they became the pattern in the storage of data for applications of processing of transactions on-line (OLTP). These tendencies are motivating the need of construction of applications object-oriented that acessem relational databases. The way of using object-oriented conception, how inheritance, to make possible the better modeling and implementation based in object-oriented database systems. Therefore, the objetc-oriented design results, also is possible to application in classics database systems. The work presents the use of project patterns in the construction of an architecture of a framework that aids the mapeamento of an application 00 to a SGBD relacional. This architecture follows the approach of set persistence of objects in gateways, that is a software layer inserted among the system database manager and the object-oriented application, whose the objective is to give support to a model of programming of applications 00. The main characteristic of this architecture is the clear separation of the classes that are about the database in relation to the classes that are about the domain of the problem of the application. This division of responsibilities allows the substitution of the referring classes the database for other, allowing the migration of the application among different databases. They are presented in this work, forms of mapping the object-oriented model for relational model. These mappings happens of the model 00 for the model relational. It is important to point out, that the architecture that it is being proposed, won't impede that structured applications let to have access to the relational database, because this approach was chosen to allow that new applications 00 has access the relational database already existent. As the implementation of this work follows the gateway approach, the concepts of object-oriented are presented, and as these they will be supported in the architecture, that is to say, which the gateway should implement.

A representação e execução de processos de negócio têm gerado importantes desafios na área de Ciência da Computação. Um desses desafios é a escolha do melhor arcabouço formal para a especificação dos controles de fluxo padrões. Algumas linguagens defendem o uso de redes de Petri ou álgebras de processos como base formal. O uso de redes de Petri para especificar workflows clássicos é uma abordagem bastante conhecida. Entretanto, pesquisas recentes vêm difundindo o uso de novas extensões da álgebra de processos como uma alternativa para a especificação formal de workflows. A principal contribuição deste trabalho é a definição da Navigation Plan Definition Language (NPDL). A NPDL foi implementada como uma extensão da linguagem SQL. Ela é uma alternativa para a representação de workflows que utiliza a álgebra de processos como arcabouço formal. A NPDL promove uma separação explícita entre o ambiente de especificação e o ambiente de execução de um workflow. Esta separação propicia o reaproveitamento de passos de negócio e o uso das propriedades da álgebra de processos não só na modelagem, mas também no controle da execução dos processos. Após a especificação de um workflow por meio da NPDL, a execução dos passos que o definem é controlada pela ferramenta NavigationPlanTool. Essa ferramenta é a segunda contribuição deste trabalho de pesquisa. / The representation and execution of business processes have generated some important challenges in Computer Science. An important related concern is the choosing of the best formal foundation to represent control-flow patterns. Some of the workflow languages advocate the Petri nets or process algebra as formal foundation. The use of Petri nets is a famous approach to support classic workflows. On the other hand some researches are introducing modern process algebra extensions as an alternative formal foundation for representing workflows. The first contribution of this research is the definition of the Navigation Plan Definition Language (NPDL). NPDL was implemented as an extension of SQL language. It is an alternative to represent business processes using process algebra as formal foundation. NPDL provides the explicit separation between specification and execution workflow environment. This separation allows reusing of business steps and usage of process algebra properties in the process modeling and execution controlling tasks. After the definition of a workflow using NPDL, the business steps execution is carried out and controlled by a tool called NavigationPlanTool. This tool is the second contribution of this research.