PATAXÓ: A Framework to Allow Updates Through XML Views

XML has become an important medium for data exchange, and is frequently used as an interface to (i.e., a view of) a relational database. Although a lot of work has been done on querying relational databases through XML views, the problem of updating relational databases through XML views has not received much attention. In this work, we map XML views expressed using a subset of XQuery to a corresponding set of relational views. Thus, we transform the problem of updating relational databases through XML views into a classical problem of updating relational databases through relational views. We then show how updates on the XML view are mapped to updates on the corresponding relational views. Existing work on updating relational views can then be leveraged to determine whether or not the relational views are updatable with respect to the relational updates, and if so, to translate the updates to the underlying relational database

Using XQuery to Build Updatable XML Views Over Relational Databases

XML has become an important medium for data exchange, and is frequently used as an interface to - i.e. a view of - a relational database. Although much attention has been paid to the problem of querying relational databases through XML views, the problem of updating relational databases through XML views has not been addressed. In this paper we investigate how a subset of XQuery can be used to build updatable XML views, so that an update to the view can be unambiguously translated to a set of updates on the underlying relational database, assuming that certain key and foreign key constraints hold. In particular, we show how views defined in this subset of XQuery can be mapped to a set of relational views, thus transforming the problem of updating relational databases through XML views into a classical problem of updating relational databases through relational views

An Improved Algorithm for Generating Database Transactions from Relational Algebra Specifications

Alloy is a lightweight modeling formalism based on relational algebra. In prior work with Fisler, Giannakopoulos, Krishnamurthi, and Yoo, we have presented a tool, Alchemy, that compiles Alloy specifications into implementations that execute against persistent databases. The foundation of Alchemy is an algorithm for rewriting relational algebra formulas into code for database transactions. In this paper we report on recent progress in improving the robustness and efficiency of this transformation

Reasoning about the updatability of XML views over relational databases

database

Conflict Resolution in Updates through XML views

Abstract. In this paper, we focus on B2B scenarios where XML views are extracted from relational databases and sent over the Web to another application that edits them and sends them back after a certain (usually long) period of time. In such transactions, it is unrealistic to lock the base tuples that are in the view to achieve concurrency control. Thus, there are some issues that need to be solved: first, to identify what changes were made in the view, and second, to identify and solve conflicts that may arise due to changes in the database state during the transaction. We address both of these issues in this paper by proposing an approach that uses our XML view update system PATAXÓ.

Um modelo de replicação com garantia de consistência em ambientes P2P com mobilidade

In unstructured distributed P2P systems there is no logical structure to control the peers coming and leaving the network, which can occur anytime due to mobility. Thus, data exchange with consistence, and data availability are very important. To favor high data availability and to acquire performance gains in dynamic behavior environments, P2P systems use data replication. However, current replication data models have a single failure point, or require complex conciliation algorithms to acquire consistency. This work introduces a replication data model that simplifies the consistency mechanism.Em sistemas P2P não-estruturados não existe uma estrutura lógica que controle a entrada e saída de nós da rede, o que pode ocorrer em qualquer tempo devido à alta mobilidade presente. Assim, é de fundamental importância a disponibilização e a troca de dados entre dispositivos presentes na rede com consistência. Para prover uma alta disponibilidade dos dados e obter ganhos de desempenho em ambientes com comportamento dinâmico, sistemas P2P utilizam-se da replicação de dados. Modelos atuais de replicação de dados possuem um ponto único de falha, ou necessitam de algoritmos muito complexos para garantir consistência. Esse trabalho apresenta um modelo de replicação que simplifica o gerenciamento de consistência de dados replicados