An increasing number of organizations are implementing data warehouses to strengthen their decision support systems. This comes with the challenges of the population and the periodic update of data warehouses. In this thesis, we present a tool that provides users with features to create a warehouse database and transform structures of the source database into structures for the warehouse database. It is highly interactive, easy to use, and hides the underlying complexity of manual SQL code generation from its users. Attributes from source tables can be mapped into new attributes in the warehouse database tables using aggregate functions. Then, relevant data is automatically transported from the source database to the newly created warehouse. The tool thus integrates warehouse creation, schema mapping and data population into a single generalpurpose tool. This tool has been designed as a component of the framework for an automated data warehouse being developed at theComputer Science Department, University of New Orleans. Users of this framework are the database administrators, who will also be able to synchronize updates of multiple copies of the data warehouse. Warehouse images that need to be updated are taken offline and applications that need to access the data warehouse can now access any of the other image warehouses. The Switching Application built into this framework switches between databases in a way that is totally transparent to applications so that they do not realize existence of multiple copies of the data warehouse. In effect, even non-technical users can create, populate and update data warehouses with minimal time and effort.

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近年來雲端運算蓬勃發展，為資訊系統的建置與服務帶來巨大的改變，其中一個重要趨勢為軟體即服務，並透過多租戶共享資源達到降低成本的優勢。因此如何讓服務可以共享資源，又能兼顧各租戶的客製化需求，這將會是軟體即服務關鍵成功因素。 為了讓租戶客製化自己的綱要，在多租戶的相關研究中，發展出各種綱要映射技術，各適用不同的狀況，但在開發應用程式時候往往無法預估租戶適合使用何種綱要映射技術。本研究提出可以讓多租戶軟體框架具有綱要映射技術的可調性，應用程式開發時候毋需考慮使用何種綱要映射技術，等租用時候再依據應用程式及租戶的特性決定。本研究將以小量租戶效能最佳的Private Table Layout與適合用於大量租戶的Universal Table Layout為例，提出的可調性多租戶實體模式來建構具有可調性的多租戶軟體框架。此外本研究提出的軟體框架經過技術的封裝，開發者不需要了解多租戶的相關技術，就能完成多租戶應用程式的開發。 / Software as a service (SaaS) is an emerging service model of cloud computing. It’s central defining characteristic is the ability for clients to use a software application on a pay-as-you-go subscription basis. However, to be economically sustainable, a SaaS application must leverage resource sharing to a large degree by accommodating different clients of the application while making it appear to each that they have the application all to themselves. In other words, a SaaS application must be a multi-tenant application. An important multi-tenant research topic is the various kinds of schema mapping technology have been developed in order for our tenants to customize their schema. However, it is hard to determine tenants’ need for particular schema mapping technology in different circumstances. This thesis proposes an adaptable schema mapping technology for a multi-tenant application (MTA) framework. The application and tenants’ characteristics do not need to be considered while applications developers are developing their schema mapping technology. This approach will take examples from the Private Table Layout mapping and the Universal Table Layout mapping to illustrate the features of this adaptable multi-tenant software framework. Furthermore, this thesis argues that, with the approach packaged as a software framework, developers are able to complete the development of a multi-tenant application without full understanding of the underlying technologies.

The aim of this dissertation is to contribute to research on pay-as-you-go data integration through the proposal of an approach for targeted feedback collection (TFC), which aims to improve the cost-effectiveness of feedback collection, especially when there is uncertainty associated with characteristics of the integration artefacts. In particular, this dissertation focuses on the data source selection task in data integration. It is shown how the impact of uncertainty about the evaluation of the characteristics of the candidate data sources, also known as data criteria, can be reduced, in a cost-effective manner, thereby improving the solutions to the data source selection problem. This dissertation shows how alternative approaches such as active learning and simple heuristics have drawbacks that throw light into the pursuit of better solutions to the problem. This dissertation describes the resulting TFC strategy and reports on its evaluation against alternative techniques. The evaluation scenarios vary from synthetic data sources with a single criterion and reliable feedback to real data sources with multiple criteria and unreliable feedback (such as can be obtained through crowdsourcing). The results confirm that the proposed TFC approach is cost-effective and leads to improved solutions for data source selection by seeking feedback that reduces uncertainty about the data criteria of the candidate data sources.

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XML est devenu le format standard d’échange de données. Nous souhaitons construire un environnement multi-système où des systèmes locaux travaillent en harmonie avec un système global, qui est une évolution conservatrice des systèmes locaux. Dans cet environnement, l’échange de données se fait dans les deux sens. Pour y parvenir nous avons besoin d’un mapping entre les schémas des systèmes. Le but du mapping est d’assurer l’évolution des schémas et de guider l’adaptation des documents entre les schémas concernés. Nous proposons des outils pour faciliter l’évolution de base de données XML. Ces outils permettent de : (i) calculer un mapping entre le schéma global et les schémas locaux, et d’adapter les documents ; (ii) calculer les contraintes d’intégrité du système global à partir de celles des systèmes locaux ; (iii) comparer les schémas de deux systèmes pour pouvoir remplacer un système par celui qui le contient ; (iv) corriger un nouveau document qui est invalide par rapport au schéma d’un système, afin de l’ajouter au système. Des expériences ont été menées sur des données synthétiques et réelles pour montrer l’efficacité de nos méthodes. / XML has become the de facto format for data exchange. We aim at establishing a multi-system environment where some local original systems work in harmony with a global integrated system, which is a conservative evolution of local ones. Data exchange is possible in both directions, allowing activities on both levels. For this purpose, we need schema mapping whose is to ensure schema evolution, and to guide the construction of a document translator, allowing automatic data adaptation wrt type evolution. We propose a set of tools to help dealing with XML database evolution. These tools are used : (i) to compute a mapping capable of obtaining a global schema which is a conservative extension of original local schemas, and to adapt XML documents ; (ii) to compute the set of integrity constraints for the global system on the basis of the local ones ; (iii) to compare XML types of two systems in order to replace a system by another one ; (iv) to correct a new document with respect to an XML schema. Experimental results are discussed, showing the efficiency of our methods in many situations.