Dissertations / Theses on the topic 'Object-relational framework'

The term impedance mismatch was first used in 1984 to label problems that arise when a program uses a relational database for storage. For example, when transferring data from a relational database into a program any relational data structure is lost because a program operates at the row level. Consequently that data structure must somehow be reproduced when data is returned to a database. There are many such mismatches that cost time and effort to address. As new programming and database languages are introduced other kinds of impedance mismatch are anticipated. Traditional approaches are concerned with pragmatic solutions to specific problems of implementation. They do not address the underlying cause and offer little rationale for the claim to a "solution". The motivation for this dissertation is to understand the cause of these mismatches so it is then possible to address each of them in an appropriate way. Problem themes are introduced as a way to make sense of impedance mismatch. Such problems are not independent Relationships between problem themes demonstrate the complex nature of impedance mismatch and they are used to identify three problems of particular significance. A structure to existing characterisations of impedance mismatch is identified and developed in order to organise the characterisations in a meaningful and useful way. This structure, based on four levels of abstraction, forms the foundation for a new framework. The framework recognises a separation of concerns between a program and a database across levels of abstraction. At each level is observed a particular kind of impedance mismatch. Through a dialogue about a correspondence at each level it is possible to understand and address each kind of mismatch in a structured and consistent way. A technique based on equivalence is introduced in support of a dialogue. The validity of the framework is demonstrated by identifying the cause of some significant mismatches. Across all the levels of the framework are explored both the cause of each mismatch and the effect of a solution. A four-stage process is described in support of an exploration and to inform others in the use of the framework. An option for change is linked to a conceptual problem not one of implementation and the fidelity and integrity of an existing solution is improved in a way that can be generalised for other solutions. New insights are also provided into the consequences of one solution. Understanding cause and effect in this level of detail is not available using an alternative framework described in the literature. However despite the improved understanding of an impedance mismatch and the consequences of a solution there is a limit to what can be achieved using the framework.

In the planning stage of web and software development, it is important to select the right tool for the job. When selecting the database to use, relational databases like MySQL is a popular choice. However, relational databases suffer by object-relational impedance mismatch. In this work we will explore the response time of relational and object-oriented databases and the overhead of ORM frameworks. This will be done by creating a web application that receives data about flights and airports from a client, which measures the response time of the databases and the entire request. It was found that MySQL has the lowest response time, while the ORM framework Hibernate adds an overhead on some of the tests while performing similar to MySQL. Db4o had the highest response time in a majority of the tests. In future works, this study could be extended by other tests or by other type of databases.

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.

När man kombinerar ett objektorienterat programmeringsspråk och en relationsdatabas uppstår en del problem för utvecklare eftersom objektorienterade programmeringsspråk och relationsdatabaser har olika fokus, objektorienterade programmeringsspråk fokuserar på att avbilda verkliga objekt och relationsdatabaser fokuserar på data. De problem som uppstår kallas med ett samlingsnamn för object-relational mismatch. Det finns flertalet ramverk för att hantera dessa problem. Ett av dem är Entity Framework.Syftet med detta projekt var att utvärdera hur utvecklare tycker att Entity Framework fungerar för att lösa problematiken runt object-relational mismatch, hur det är för utvecklare att lära sig använda Entity Framework samt hur tillgången på inlärningsmaterial är.Under vår studie har vi lärt oss använda Entity Framework samtidigt som vi gjort en studie av tillgången på inlärningsmaterial. Vi har också byggt om en applikation så att den använder Entity Framework. Vi har jämfört den ombyggda applikationen med den gamla applikationen för att kunna se vilken skillnad som Entity Framework bidrog till.Vi kom fram till att Entity Framework hanterar object-relational mismatch på ett bra sätt som bland annat gör att utvecklingsprocessen kortas ner då inte lika mycket kod behöver skrivas. Utvecklare med tidigare kunskaper i .NET-programmering upplever att det är lätt att lära sig Entity Framework. Att det upplevs lätt att lära sig Entity Framework hänger förmodligen ihop med att tillgången på inlärningsmaterial är god.

Este trabalho apresenta o desenvolvimento de um Framework de persistência que utiliza banco de dados objeto-relacional como mecanismo de persistência. Tendo por objetivo usar os conceitos de orientação a objetos descritos na norma SQL:2008, conceitos como: objeto (atributos e métodos), herança, agregação, composição, referências (REF) e estruturas multivaloradas (arrays e multiset). Para tanto se desenvolveu e formalizou (XSD) um arquivo XML que representa um esquema de objetos através da norma SQL:2008. Da mesma forma definiu-se um conjunto de anotações Java, com o intuito de facilitar a utilização e configuração do Framework, o qual é chamado de O-ODBM (Object Object-Relational Database Management).
Persistent Frameworks have been used to aid developers, managing all access to DBMS. This kind of tool maps objects from OO applications to relational databases. Besides, allow developers to persist objects without solid knowledge about DBMSs and specific languages, making better the developers productivity, mainly when different DBMS is used. On the other hands, since 1999 the SQL specification has introduced new features to manipulate objects in relational databases which since then has been called Object-Relational Database (ORDB). At present, many DBMS offer resources to manipulate objects in database, but the most of the application developers just map class to relations tables, failing to exploit the strength of O-R model. The lack of the tools that aid the project of database contributes to this situation. Considering the vantages of use of the persistent frameworks and the ORDBs, this article introduces the O-ODM (Object-Object Database Mapping) a persistent framework for relational object databases.

This work is analyzing problems, arising because of sematical gap between relational and object-oriented approaches and discusses how to utilize object-relational mapping for solving this problem. After analysis of object-relational mapping framework (further – ORM) principles and features of existing ORM frameworks a model is suggested, that allows to implement ORM by utilizing MVP principles in a way that retains major portion of both approach pros and is perfect for transitioning existing relational structures to object-oriented. Further, project and implementation of prototype framework, that uses the following principles and suggested model, is described and utilized as for implementing imaginary domain ORM mapping example application.

This diploma work deals with design and implementation of the database neutral object-relational (OR) layer in C++ language over inherited database. The goal is to create the layer to encase the access to database from the application layer. Suggested layer will stem from the object-relation mapping technology, which is currently available for many object-programming language, such as C#, Java or Visual Basic. The work consists of three main parts. The forepart is focused on clearing object-relation mapping technology. It briefly overviews differences in capabilities and levels of implementation of various approaches. The next part describes significant properties of databases considered as back-ends for data storage in the project. The aim of this part is to present enough information to support database neutral design of the OR layer. The rest of the document deals with design and implementation of OR layer for the considered environment followed by the summarization of results and overall evaluational.

Denna uppsats mäter och jämför prestanda mellan en objektorienterad databas och en relationsdatabas. Uppsatsen bygger på en utredande karaktär utifrån vår hypotes och vårt intresse att testa den.Hypotesen bygger på problematiken omkring mängden kod utvecklaren måste skriva för att kunna koppla ihop applikation med databas. En större mängd skriven kod som utvecklaren måste skriva borde göra att prestanda och svarstider blir långsammare. Därför ville vi undersöka om verktyg som medför en mindre mängd skriven kod kan förbättra prestandan och ge snabbare svarstider. Vi valde att testa vår hypotes mellan ADO. NET relationsdatabas och ADO. NET Entity Framework objektorienterade databas då ADO. NET genererar större mängd kod och Entity Framework innehåller verktyg som i sin tur genererar mindre mängd kod. För att kunna mäta och jämföra prestandan utvecklades en mindre kundapplikation kopplad med respektive ramverks databasmodell där båda använder sig av samma databas. Genom att mäta prestandan har vi kunnat jämföra de olika modellerna och då även kunnat se vilka fördelar och nackdelar respektive modell genererat. Vi har även mätt antal kodrader och diskuterat hur det påverkar kostnaden av systemutvecklingen samt underhållbarheten för applikationen. Det som framförallt framkom var att relationsdatabasen resulterade i en något snabbare prestanda mätt i millisekunder trots att antal kodrader blev fler jämfört med en objektorienterad databas. Den objektorienterade databasen resulterade i något sämre prestanda men med färre antal skrivna kodrader. Det medför att den kräver mindre underhåll i koden vid förvaltning av den nya applikationen. Det innebär även att tiden vid utveckling för den vane programmeraren minskar med cirka 50 % och därmed sjunker även utvecklingskostnaden, under förutsättning att en något långsammare prestanda kan accepteras.

Denna rapport presenterar en undersökning av sex olika objekt-relationsmappningsramverk, nämligen Entity Framework, LINQ to SQL, NHibernate, Castle ActiveRecord, MyGeneration Doodads och Subsonic. Undersökningen redogör för styrkor och svagheter hos de olika ramverken samt diskuterar när respektive ramverk är lämpligt att använda.

De ramverk som bedömdes vara mest intressanta var NHibernate och Entity Framework, då de erbjuder flexibel mappning mellan domänmodellen och det underliggande databasschemat samt god tillgång till dokumentation och litteratur.

Undersökningen användes som grund för att besluta vilket av de aktuella ramverken som skulle användas vid en omskrivning av en existerande applikation för IT-konsultföretaget Sogeti. Det ramverk som ansågs mest lämpligt för applikationen var NHibernate.

This report presents a study of six different object-relational mapping frameworks, namely Entity Framework, LINQ to SQL, NHibernate, Castle ActiveRecord, MyGeneration Doodads and Subsonic. The study describes the strengths and weaknesses of the various frameworks and discusses when each framework is appropriate to use.

The frameworks that were judged to be the most interesting were NHibernate and Entity Framework, since they provide flexible mapping between the domain model and the underlying database schema as well as good availability of documentation and literature.

The study was used as a basis for deciding which of the frameworks that should be used in a rewrite of an existing application for the IT consulting company Sogeti. The framework that was considered the most appropriate for the application was NHibernate.

Em diversos serviços de radioterapia brasileiros há a premente necessidade de sistematização de processos que ainda hoje, mesmo com acesso à tecnologia da informação, é realizada manualmente. Este fato acontece com o controle dos pacientes em planejamento radioterápico onde os dados de todas as etapas do processo são inseridos em um quadro físico conforme executadas. Esses dados consistem desde o agendamento da tomografia de planejamento até a liberação do mesmo para o tratamento. O objetivo deste estudo é o desenvolvimento de um software para controle eletrônico de pacientes em processo de planejamento radioterápico, substituindo o quadro físico utilizado atualmente. Foi utilizado para este estudo a técnica de elicitação de requisitos, que resulta em um documento de requisitos que serve de base para a modelagem do sistema através de diagramas UML e modelagem conceitual do banco de dados MySql e posteriormente a utilização da técnica de mapeamento objeto relacional (MOR). A consistência nos dados permite acesso seguro e confiável à esses dados, facilita a obtenção de dados estatísticos e agiliza o processo de planejamento, já que de posse de estatísticas consistentes é possível a identificação de gargalos no processo e sua resolução com maior rapidez. O resultado deste estudo é um software e banco de dados que integra todas as informações do processo de planejamento radioterápico.
In Brazilian radiotherapy departments there is a pressing need for systematization of processes, that even today with the access of information technology is performed manually. The control of the patients in radiotherapy planning with the data of all the steps of the process are inserted in a physical board as they are executed. These data consist of scheduling since the planning tomography until the release of the patient for the treatment. The objective of this study is the development of a software for electronic control of patients in radiotherapy planning process, replacing the physical board currently used. The requirements for the elicitation technique was used for this study, which results in a requirements document that serves as the basis for modeling the system through UML diagrams and conceptual modeling of the MySql database and after using the relational object mapping technique (MOR). The data consistency allows secure and reliable access to these data, facilitates the collection of statistical data and streamlines the planning process, this consistent statistics allow the identification of limitation in the process and faster resolution. The result of this study is a software and database that integrates all the information of the radiotherapy planning process.

Context: Information technology is playing an important role in creating innovation in business. Due to increase in demand of information technology, web development has become an important field. PHP is an open source language, which is widely used in web development. PHP is used to develop dynamic web pages and it has the ability to connect with database. PHP has some good features i.e. cross platform compatibility, scalability, efficient execution and is an open source technology. These features make it a good choice for developers to choose PHP for web development. The maintenance of an application becomes difficult and performance being considerably reduced, if PHP is to be used without using its frameworks. To resolve these issues, different frameworks have been introduced by web development communities on the internet. These frameworks are based on Model, View, Controller design pattern. These frameworks provide, different common functionalities and classes in the form of helpers, components, and plug-in to reduce the development time. Due to these features like robustness, scalability, maintainability and performance, these frameworks are mostly used for web development in PHP, with performance being considered the most important factor. Objectives:The objective of this thesis is to compare and analyze the affect of data abstraction layer (ORM) on the performance of two PHP frameworks. These two frameworks are CakePHP and CodeIgniter. CAKEPHP has built-in support of object-relational mapping (ORM) but CodeIgniter has no built-in support of object-relational mapping (ORM). We considered load testing and stress testing to measure the performance of these two frameworks. Methods: We performed the experiment to show the performance of CakePHP (with ORM) and CodeIgniter (no ORM) frameworks. We developed two applications in both the PHP frameworks, with the same scope and design and measured the performance of these applications, with respect to load testing, with automated testing tool. The results have been obtained by testing the performance of both the applications on local and live servers. Conclusions:After analyzing the results we concluded that CodeIgniter is useful for small and medium sized applications. But CAKEPHP is good for large and enterprise level applications, as in stress conditions the CAKEPHP performed better than CodeIgniter on both local and live environment.

The aim of this study is to analyze the Django framework in terms of design patterns and architectural principles with emphasis on development of information systems. Based on a comparison of two real systems was identified basic general functionality, the systems commonly support. This analysis helped identify the strengths and weaknesses of the framework. These ensue from the application architecture and from weaknesses of some of its components. Based on these were derived requirements for library expansion and new application components. Problems that have arisen with the solution of the new application components within the specified requirements are theoretically analyzed and described their solutions with emphasis on the application of appropriate design patterns. The solution here appears the Observer design pattern in an environment different processes, access control entries (pessimistic and optimistic locking) and a database schema in an incremental approach to the development of an information system. Implemented components were used to program information system in a team, which demonstrates the overall suitability of this framework for use in the development of information systems.

Dissertação de mestrado em Engenharia de Informática
Today, most software applications require mechanisms to store information persistently. For decades, Relational Database Management Systems (RDBMSs) have been the most common technology to provide efficient and reliable persistence. Due to the object-relational paradigm mismatch, object oriented applications that store data in relational databases have to deal with Object Relational Mapping (ORM) problems. Since the emerging of new ORM frameworks, there has been an attempt to lure developers for a radical paradigm shift. However, they still often have troubles finding the best persistence mechanism for their applications, especially when they have to bear with legacy database systems. The aim of this dissertation is to discuss the persistence problem on object oriented applications and find the best solutions. The main focus lies on the ORM limitations, patterns, technologies and alternatives. The project supporting this dissertation was implemented at Cachapuz under the Project Global Weighting Solutions (GWS). Essentially, the objectives of GWS were centred on finding the optimal persistence layer for CazFramework, mostly providing database interoperability with close-to-Structured Query Language (SQL) querying. Therefore, this work provides analyses on ORM patterns, frameworks, alternatives to ORM like Object-Oriented Database Management Systems (OODBMSs). It also describes the implementation of CazDataProvider, a .NET library tool providing database interoperability and dynamic query features. In the end, there is a performance comparison of all the technologies debated in this dissertation. The result of this dissertation provides guidance for adopting the best persistence technology or implement the most suitable ORM architectures.
Hoje, a maioria dos aplicações requerem mecanismos para armazenar informação persistentemente. Durante décadas, as RDBMSs têm sido a tecnologia mais comum para fornecer persistência eficiente e confiável. Devido à incompatibilidade dos paradigmas objetos-relacional, as aplicações orientadas a objetos que armazenam dados em bases de dados relacionais têm de lidar com os problemas do ORM. Desde o surgimento de novas frameworks ORM, houve uma tentativa de atrair programadores para uma mudança radical de paradigmas. No entanto, eles ainda têm muitas vezes dificuldade em encontrar o melhor mecanismo de persistência para as suas aplicações, especialmente quando eles têm de lidar com bases de dados legadss. O objetivo deste trabalho é discutir o problema de persistência em aplicações orientadas a objetos e encontrar as melhores soluções. O foco principal está nas limitações, padrões e tecnologias do ORM bem como suas alternativas. O projeto de apoio a esta dissertação foi implementado na Cachapuz no âmbito do Projeto GWS. Essencialmente, os objetivos do GWS foram centrados em encontrar a camada de persistência ideal para a CazFramework, principalmente fornecendo interoperabilidade de base de dados e consultas em SQL. Portanto, este trabalho fornece análises sobre padrões, frameworks e alternativas ao ORM como OODBMS. Além disso descreve a implementação do CazDataProvider, uma biblioteca .NET que fornece interoperabilidade de bases de dados e consultas dinâmicas. No final, há uma comparação de desempenho de todas as tecnologias discutidas nesta dissertação. O resultado deste trabalho fornece orientação para adotar a melhor tecnologia de persistência ou implementar as arquiteturas ORM mais adequadas.

As the Object-Oriented programming technique becomes more and more popular in contemporary software design, issues related to persistent objects must be addressed. This thesis introduces a framework for Object-Relational Mapping. The framework is intended to simplify the handling of persistent objects in a Relational Database System. The framework's architecture consists of two layers: an object layer that contains the infrastructure for persistent objects and a storage layer that provides an interface to the Physical Storage System. As contributions, I have introduced my original work including mapping inheritance with inheritance, a particular solution for aggregation and associations mapping, a cache of object references for constructing objects and name conventions for preserving object maps. The Framework for Object-Relational Mapping is a C++ Framework (a set of Classes). It supports most of relational database systems. Developers can use these classes to obtain abilities about object relational mapping. In this thesis, a teaching assignment planner project is used to test my framework's performance in saving coding work.

碩士
義守大學
資訊管理學系碩士班
93
In recent years, with the development of the medical informatics and the rapid change of the medical organization management environment, how to integrate effectively the intra of medical information in order to aid analysis the decision level has already become a new agitation of medical informatics. For this reason, a lot of medium-and-large-sized medical organizations have set about introducing the so-called clinical data warehouse system at every moment and hope to use the well-established data warehouse structure in the business world to meet the information demand for various medical decisions and analyses. However, the current data warehouse system is built upon the relation database, the star-schema is only suitable for dealing with the characters, numeral, and it is a multi-dimension statistical analysis of observing the field change of number value directly. With regard to a great deal of non-characters and non-numeral medical data, such as comprehensive image file for instance the X-ray, ECG, Ultrasound, CT and prescription, etc., it is unable to offer effectively organization, store, integration and analysis of heterogeneous data. For this reason, in this research, we propose a new data warehouse architecture based on the Object-Relational Database, and propose a data model which is suitable for the Object-Relational data warehouse. The feasibility of the proposed data model is illustrated with the construction of the clinical data warehouse and data mart over some disease instances.

碩士
中原大學
資訊管理研究所
101
Internet makes the development of information technology has been a major advancement in the enterprise business model can closely, but the information update speed is too quick, allow enterprises to more traditional architecture complex and difficult to maintain, unable to cope with the changes required, it makes a Service Oriented Architecture (SOA) to cope with these problems. Service oriented architecture is defined as the main service and the loosely coupled between services must be distributed architecture, each capable of independent execution services and working, and its purpose is to enable information systems to be reached with the change requirements. However, the traditional architecture of the system is not making further divide the data tier, making data connections, processing and maintenance of the coupling is high, resulting in time-consuming and difficult to maintain development to happen, this study will be an object-relational mapping framework technology to improve existing technical problems. Use of service-oriented architecture brings advantages, and distributed system architecture for data-tier persistence layer divided, and use object-relational mapping framework technologies discussed in the persistence layer to do. Understand the current object-relational mapping framework technology is able to achieve the needs of service-oriented architecture, enabling enterprises to frequent changes in response to the needs and to enhance the effectiveness of its development and maintenance.