User Defined Types and Nested Tables in Object Relational Databases

Bernadette Byrne, Mary Garvey, ‘User Defined Types and Nested Tables in Object Relational Databases’, paper presented at the United Kingdom Academy for Information Systems 2006: Putting Theory into Practice, Cheltenham, UK, 5-7 June, 2006.There has been much research and work into incorporating objects into databases with a number of object databases being developed in the 1980s and 1990s. During the 1990s the concept of object relational databases became popular, with object extensions to the relational model. As a result, several relational databases have added such extensions. There has been little in the way of formal evaluation of object relational extensions to commercial database systems. In this work an airline flight logging system, a real-world database application, was taken and a database developed using a regular relational database and again using object relational extensions, allowing the evaluation of the relational extensions.Peer reviewe

A Knowledge Transfer Partnership - the development of a Bespoke Enterprise Resource Planning System in the UK

Abstract. A Knowledge Transfer Partnerships (KTP) is a UK-wide programme designed to enable businesses to improve their competitiveness, productivity and performance. A KTP achieves this through the forming of a Partnership between a business and an academic institution. The aim is to enable businesses to access skills and expertise from academics and embed this knowledge in their businesses in order to develop the business. The knowledge sought is embedded into the business through a project, or projects, undertaken by a recently qualified person (known as the Associate). Part funding is provided by the government towards the Associate’s salary and towards the release of an Academic supervisor who works a half a day a week at the company. KTPs can vary in length from 6 months to three years, depending on the needs of the business and the desired outcomes. Therefore a KTP enables new capability to be embedded into the business and has benefited and continues to benefit a wide range of businesses across many sectors in the UK, including micro sized, small and large businesses across many sectors. This paper describes a Knowledge Transfer Partnership project between the University of Hertfordshire and a small and medium sized enterprise (SME) based in Cambridgeshire, UK.Final Accepted Versio

Temporal Support in Relational Databases

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. © 2012 Higher Education AcademyThis paper examines the current state of temporal support in relational databases and the type of situations where we need that support. There has been much research in this area and there were attempts in the American National Standards Institute (ANSI) and the International Organisation for Standardisation (ISO) standards committees in the late 1990s to add an extension called TSQL2 to the existing SQL standard. However no agreement could be reached as it was felt that some of the suggested extensions did not fit well with the relational model, as well as being difficult to implement. TSQL2 was abandoned and since then vendors have added their own data types, and if we are lucky, operators too in an attempt to provide support. However, to novice students and database designers it is often not apparent why some temporal concepts are difficult to deal with in a relational database. In teaching these concepts to students we use a Case Study (based on a real example) which illustrates the problems of providing temporal support by using examples of the data types which could be useful to solve temporal problems and the operators which are necessary to provide this

The Design and Implementation of a bespoke Enterprise Resource Planning System (ERP) for an acoustical engineering company

This paper will describe the tasks completed so far as part of a Knowledge Transfer Partnership between the University of Hertfordshire and Acoustical Control Engineers (ACE) a ‘small and medium sized enterprise’ (SME) based in Cambridgeshire, UK. ACE’s 25 personnel design, manufacture and install noise and vibration control systems to solve a wide range of acoustic problems. The projects undertaken include acoustic enclosures for supermarket refrigeration plant and for generators used in many situations, together with other more diverse applications such as controlling noise in the workplace and even on a luxury boat. Before the current KTP project the company used some partially computerised systems consisting of spreadsheets to perform acoustic analyses, pricing and project management functions supplemented with a paper based system to ‘fill the gaps’. Enterprise Resource Planning (ERP) systems provide an integrated database for all parts of the organisation allowing decisions to be based on a complete understanding of the organisation’s information, avoiding the problems due to duplication of data and ensuring that the consequences of decisions in one part of the organisation are reflected in the planning and control systems of the rest of the organisation. ERP systems became popular from the 1990’s mainly in relatively large organisations due to the complexity and cost of these systems. This project is unusual in that rather than adapting an off-the-shelf ERP solution to ACE’s very specific and specialised requirements we are taking an ERP development approach in an SME whose legacy systems are made up of spreadsheet and paper based systems. For the software development an Agile approach has been used. Agile involves software development methods based on iterative and incremental development. The initial attempt was to start developing the ERP from an Open Source ERP Source Code; however this effort was futile as a result of the bespoke nature of ACE’s business and product lines. Mapping ACE’s data model to the database which any existing ERP system could be adapted to, proved to be a very difficult problem. Therefore, developing the ERP from first principles was inevitable. Several of the ERP modules have been developed, user training has taken place and the core modules have been signed off. The project is due to complete in September 2014 and by this time we will have further information on how the ERP system has increased the competitiveness of the company, as well as experience of introducing an ERP into an SME. However, as would be expected the work undertaken developing the system so far has had several significant effects on ACE and acted as a catalyst for change in various parts of ACE’s business.Non peer reviewe

The teaching of Relational On-Line Analytical Processing (ROLAP) in Advanced Database courses.

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. © 2012 Higher Education AcademyDatabases are taught as a core subject at undergraduate and postgraduate levels in computer science degrees. The subject is often divided into conceptual database design and database technologies including physical database design. One of the problems with teaching the topic of ROLAP and Data Warehousing is the difficulty of providing practical exposure to the students. The approach taken in this work is intended to help students apply their knowledge learnt throughout the subject and gain some practical understanding leading to its application and implementation which furthermore provides the basis for analysis and evaluation at the level of critical analysis that would be expected on an advanced level course and at the highest level of learning taxonomies. In our work we have reverse engineered a large Oracle sample dataset and adapted it for use in the teaching of ROLAP. We have also produced our own smaller sample dataset for simplification and understanding of complex queries involving Slicing, Dicing , Pivoting, Rollup and Cube operations. In our examples ROLAP operations and their alternative SQL approaches are performed to provide multi-dimensional results

Increased Question Sharing Between E-Learning Systems

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Interoperability Between ELearning Systems

Online assessments are an integral part of eLearning systems that enhance both distance and continuous education. Although over two-hundred and fifty eLearning applications exist, most educational institutions are trapped with a particular vendor primarily due to lack of in test-question sharing features. This paper highlights the evolution of eLearning systems whilst detailing the two most prominent objective test question standards, namely, QML and QTI. An analysis conducted amongst software houses which are involved in the development of eLearning systems confirms the fact that most applications make use of proprietary formats and clearly shows a lack of import and export options amongst other features

UML Class Diagram or Entity Relationship Diagram : An Object Relational Impedance Mismatch

It is now nearly 30 years since Peter Chen’s watershed paper “The Entity-Relationship Model –towards a Unified View of Data”. [1] The entity relationship model and variations and extensions to ithave been taught in colleges and universities for many years. In his original paper Peter Chen looked at converting his new ER model to the then existing data structure diagrams for the Network model. In recent years there has been a tendency to use a Unified Modelling Language (UML) class diagram forconceptual modeling for relational databases, and several popular course text books use UMLnotation to some degree [2] [3]. However Object and Relational technology are based on different paradigms. In the paper we argue that the UML class diagram is more of a logical model (implementation specific). ER Diagrams on theother hand, are at a conceptual level of database design dealing with the main items and their relationships and not with implementation specific detail. UML focuses on OOAD (Object Oriented Analysis and Design) and is navigational and program dependent whereas the relational model is set based and exhibits data independence. The ER model provides a well-established set of mapping rules for mapping to a relational model. In this paper we look specifically at the areas which can cause problems for the novice databasedesigner due to this conceptual mismatch of two different paradigms. Firstly, transferring the mapping of a weak entity from an Entity Relationship model to UML and secondly the representation of structural constraints between objects. We look at the mixture of notations which students mistakenly use when modeling. This is often the result of different notations being used on different courses throughout their degree. Several of the popular text books at the moment use either a variation of ER,UML, or both for teaching database modeling. At the moment if a student picks up a text book they could be faced with either; one of the many ER variations, UML, UML and a variation of ER both covered separately, or UML and ER merged together. We regard this problem as a conceptual impedance mismatch. This problem is documented in [21] who have produced a catalogue of impedance mismatch problems between object-relational and relational paradigms. We regard the problems of using UML class diagrams for relational database design as a conceptual impedance mismatch as the Entity Relationship model does not have the structures in the model to deal with Object Oriented concepts Keywords: EERD, UML Class Diagram, Relational Database Design, Structural Constraints, relational and object database impedance mismatch. The ER model was originally put forward by Chen [1] and subsequently extensions have been added to add further semantics to the original model; mainly the concepts of specialisation, generalisation and aggregation. In this paper we refer to an Entity-Relationship model (ER) as the basic model and an extended or enhanced entity-relationship model (EER) as a model which includes the extra concepts. The ER and EER models are also often used to aid communication between the designer and the user at the requirements analysis stage. In this paper when we use the term “conceptual model” we mean a model that is not implementation specific.ISBN: 978-84-616-3847-5 3594Peer reviewe

The Use of UML Class Diagrams To Teach Database Modelling and Database Design

It is now nearly 30 years since Peter Chen’s watershed paper “The Entity-Relationship Model – towards a Unified View of Data”. [1] The entity relationship model and variations and extensions to it have been taught in colleges and universities for many years. In his original paper Peter Chen looked at converting his new ER model to the then existing data structure diagrams for the Network model. In recent years there has been a tendency to use a Unified Modelling Language (UML) class diagram for conceptual modelling for relational databases, and several popular course text books use UML notation to some degree [2] [3]. This paper looks at the usefulness of using UML class diagrams for teaching database design in undergraduate courses. In this paper we look specifically at two concepts which can cause problems for the novice database designer. Firstly transferring the concept of a weak entity from an Entity Relationship model to UML and secondly the notation for structural constraints in different diagramming notations. We also look at the mixture of notations which students mistakenly use when modelling. This is often the result of different notations being used on different courses throughout their degree. Peter Chen wrote in his original paper “The entity-relationship model can be used as a tool in the structured design of databases using the network model” today we could write “the UML class diagram can be used as a tool in the structured design of databases using the relational model”. Or can we

A geospatial assessment of the rooftop decarbonisation potential of industrial and commercial zoned buildings: an example of Irish cities and regions

peer-reviewedThis paper describes a framework for estimating the effectiveness of photovoltaic and rainwater harvesting technology deployment on industrial and commercial zoned buildings to facilitate reducing national GHG emissions. Decarbonisation technologies pathways were investigated which may aid in meeting national decarbonisation targets, and their potential role at local administrative area scale evaluated. A finding arising from application of this method was that a small number of larger industrial and commercial buildings, representing only 4% of the sectors buildings, were found to account for 38% of its decarbonisation potential. Future carbon emission scenarios identified that electricity demand may be expected to increase for the industrial and commercial sector up to 2030, and that the technological potential for current photovoltaics systems have the potential to reduce GHG emissions by 4% more than currently planned Irish grid-scale decarbonisation trajectories. The method may be adopted at European scale, using local data on climate and building attributes, and is applicable at national, regional and local scales. The paper concludes with a review of technologies which may aid further decarbonisation studies, which include improved data availability for 3D building generation, and enabling technologies such as machine learning algorithms applied to satellite imagery.PUBLISHEDpeer-reviewe