Open issues in semantic query optimization in relational DBMS

After two decades of research into Semantic Query Optimization (SQO) there is clear agreement as to the efficacy of SQO. However, although there are some experimental implementations there are still no commercial implementations. We first present a thorough analysis of research into SQO. We identify three problems which inhibit the effective use of SQO in Relational Database Management Systems(RDBMS). We then propose solutions to these problems and describe first steps towards the implementation of an effective semantic query optimizer for relational databases

Temporal and Contextual Dependencies in Relational Data Modeling

Although a solid theoretical foundation of relational data modeling has existed for decades, critical reassessment from temporal requirements’ perspective reveals shortcomings in its integrity constraints. We identify the need for this work by discussing how existing relational databases fail to ensure correctness of data when the data to be stored is time sensitive. The analysis presented in this work becomes particularly important in present times where, because of relational databases’ inadequacy to cater to all the requirements, new forms of database systems such as temporal databases, active databases, real time databases, and NoSQL (non-relational) databases have been introduced. In relational databases, temporal requirements have been dealt with either at application level using scripts or through manual assistance, but no attempts have been made to address them at design level. These requirements are the ones that need changing metadata as the time progresses, which remains unsupported by Relational Database Management System (RDBMS) to date. Starting with shortcomings of data, entity, and referential integrity in relational data modeling, we propose a new form of integrity that works at a more detailed level of granularity. We also present several important concepts including temporal dependency, contextual dependency, and cell level integrity. We then introduce cellular-constraints to implement the proposed integrity and dependencies, and also how they can be incorporated into the relational data model to enable RDBMS to handle temporal requirements in future. Overall, we provide a formal description to address the temporal requirements’ problem in relational data model, and design a framework for solving this problem. We have supplemented our proposition using examples, experiments and results

Data Management in Microservices: State of the Practice, Challenges, and Research Directions

We are recently witnessing an increased adoption of microservice architectures by the industry for achieving scalability by functional decomposition, fault-tolerance by deployment of small and independent services, and polyglot persistence by the adoption of different database technologies specific to the needs of each service. Despite the accelerating industrial adoption and the extensive research on microservices, there is a lack of thorough investigation on the state of the practice and the major challenges faced by practitioners with regard to data management. To bridge this gap, this paper presents a detailed investigation of data management in microservices. Our exploratory study is based on the following methodology: we conducted a systematic literature review of articles reporting the adoption of microservices in industry, where more than 300 articles were filtered down to 11 representative studies; we analyzed a set of 9 popular open-source microservice-based applications, selected out of more than 20 open-source projects; furthermore, to strengthen our evidence, we conducted an online survey that we then used to cross-validate the findings of the previous steps with the perceptions and experiences of over 120 practitioners and researchers. Through this process, we were able to categorize the state of practice and reveal several principled challenges that cannot be solved by software engineering practices, but rather need system-level support to alleviate the burden of practitioners. Based on the observations we also identified a series of research directions to achieve this goal. Fundamentally, novel database systems and data management tools that support isolation for microservices, which include fault isolation, performance isolation, data ownership, and independent schema evolution across microservices must be built to address the needs of this growing architectural style

An Architecture to infer Business Rules from Event Condition Action Rules implemented in the Persistence Layer

The business rules that govern the behaviour of a business process can be hardcoded in different ways in a software application. The modernization or improvement of these applications to a process-oriented perspective implies typically the modification of the business rules. Frequently, legacy systems are not well-documented, and almost always, the documentation they have is not updated. As a consequence many times is necessary the analysis of source code and databases structures to be transformed into a business language more understandable by the business experts involved in the modernization process. Database triggers are one of the artefacts in which business rules are hardcoded. We focus on this kind of artefacts, having in mind to avoid the manual analysis of the triggers by a database expert, and bringing it closer to business experts. To get this aim we need to discover business rules that are hardcoded in triggers, and translate it into vocabularies that are commonly used by business experts. In this paper we propose an ADM-based architecture to discover business rules and rewrite then into a language that can be understood by the business experts.Ministerio de Ciencia y Tecnología TIN2009-13714Ministerio de Ciencia y Tecnología TIN2010-20057-C03-02Ministerio de Ciencia y Tecnología TIN2010-21744-C02-

Environmental information systems : the development and implementation of the Lake Rukwa Basin integrated project environmental information system (LRBIP-EIS) database, Tanzania

Bibliography: leaves 91-97.The quest for sustenance inevitably forces mankind to exploit natural resources found within their environs. In many cases, the exploitation results in massive environmental degradation that disrupts the ecosystem and causes loss of bio-diversity. There is generally a lack of information systems to monitor and provide quantitative information on the state of the affected environment. Decision-makers usually fail to make informed decisions with regard to conservation strategies. The need to provide decision-makers with quantitative environmental information formed the basis of this thesis. An integrated environmental information system (EIS) database was developed according to the Software Development Methodology for three of the identified environmental sectors. This involved detailed user needs assessment to identify the information requirements (both spatial and textual) for each sector. The results were used to design separate data models that were later merged to create an integrated data model for the database application. A fisheries application prototype was developed to implement the proposed database design. The prototype has three major components. The Geographic Information System (GIS) handles the spatial data such as rivers, settlements, roads, and lakes. A relational database management system (RDBMS) was used to store and maintain the non-spatial data such as fisherman ' s personal details and fish catch data. Customized graphical user interfaces were designed to handle the data visualization and restricted access to the GIS and RDBMS environments

An integrated information system to support energy policy formulation in South Africa : a conceptual study

Ph.D. (Energy Studies)The underlying assumption of this thesis is that information is critical for effective energy policy support. The objectives set and attained for this study were to: • assess existing solutions to the problem of supplying energy information; • consider developments in integrated conceptual solutions to the problems; • identify and analyse data structures for providing a single integrated information system as a solution; • evaluate and identify local energy and economic data sources for input to the proposed system; • provide a framework for information outputs in such an integrated system; and • make recommendations on the practical implementation of the conceptual . solution. The concepts underlying the basic assumption, and other parameters were clarified in Chapter 1. In particular, the link between policy formulation, modeling, and data collection, management and dissemination was shown. A study and assessment of existing energy information systems was then carried out. This investigated national systems in South Africa and other countries, and the systems of three international organisations. The structure and management of these energy information systems was assessed, as was the degree to which each provided the necessary support for policy formulation. Legislation was, where applicable, also considered. It was determined from this study and assessment that there were no integrated information systems to provide adequate information for energy policy makers through a single access point. An integrated single access point system was postulated at the conceptual level in Chapter 3. The major contribution to this conceptualisation is the concept of a single standardised referential data set A single referential data set can be used to classify all data at every level of the proposed integrated national energy information system. This integrated approach supports policy formulation and allows for the most efficient use of national resources in maintaining information. The proposed system was considered as a data flow model, to provide an overview of the collection, processing and dissemination of data. Next, a system model was developed. This divided the system into two broad divisions: the central control functions, including the referential data set; and the data modules, which provide the structure for capturing and maintaining the collected data. The final stage in this chapter . was the development of a data model which shows the relationships between the elements of the system model, particularly the relationship between the referential data set and all other data. In Chapter 4, this data model was developed further to identify entity sets and their content descriptions. It indicates in tabular format the structure of the different system components, and then shows diagrammatically the high level linkages between these components; This analysis of the proposed system is the precursor to work by systems analysts who are responsible for the final design specifications for system software. In Chapter 5 the objective was to determine sources of data for input to the national system. The South African energy economy was briefly studied and assessed for both supply and demand side information. Finally in Chapter 6, a set of output templates was developed. Once fully implemented, these will provide system users with all the necessary information to support policy formulation. Desired outputs from a system must be known before the system is designed, and are therefor included