Federated Database Management System Research Articles

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This paper presents a vision and description for query control, which is a paradigm for database access control. In this model, individual queries are examined before being executed and are either allowed or denied by a pre-defined policy. Traditional view-based database access control requires the enforcer to view the query, the records, or both. That may present difficulty when the enforcer is not allowed to view database contents or the query itself. This discussion of query control arises from our experience with privacy-preserving encrypted databases, in which no single entity learns both the query and the database contents. Query control is also a good fit for enforcing rules and regulations that are not well-addressed by view-based access control. With the rise of federated database management systems, we believe that new approaches to access control will be increasingly important.

A learning optimizer for a federated database management system

Optimizers in modern DBMSs utilize a cost model to choose an efficient query execution plan (QEP) among all possible plans for a given query. The accuracy of the cost estimates depends heavily on accurate statistics about the underlying data. Outdated statistics or wrong assumptions in the underlying statistical model frequently lead to suboptimal selection of execution plans and thus to bad query performance. Federated systems require additional statistics on remote data to be kept on the federated DBMS in order to choose the most efficient execution plan when joining data from different data sources. Wrong statistics within a federated DBMS can cause not only suboptimal data access strategies but also unbalanced workload distribution as well as unnecessarily high network traffic and communication overhead. The maintenance of statistics in a federated DBMS is troublesome due to the independence of the remote DBMSs that might not expose their statistics or use different models and not collect all statistics needed by the federated DBMS. We present an approach that extends DB2’s learning optimizer to automatically find flaws in statistics on remote data by extending its query feedback loop towards the federated architecture. We will discuss several approaches to get feedback from remote queries and present our solution that utilizes local query feedback and remote query feedback to retrieve information needed to compute statistics profiles. We provide a detailed performance study and analysis of our approach, and demonstrate in a case study a potential query execution speedup of orders of magnitude while only incurring a moderate overhead during query execution.

A CORBA-based multidatabase system—Panorama project

Panorama is a multidatabase system (MDBS) developed in HUST. The project aims to achieve interoperability among existing, heterogeneous, federated database management systems such as Oracle8, Sybase, and DM2 (A database management system developed at HUST, Wuhan, China). This system is based on OMG’s distributed object management architecture and it is implemented on top of CORBA compliant, namely VisiBroker, which is used as its infrastructure. Panorama can provide its users a single common data model and a single global query language named PanoSQL, which make it possible to incorporate different databases into the system. The main component of this system are interfaces for the Local DBMSs that participate in Panorama, a transaction manager, a common data model, a schema integrator, a global query language, and a global query processing and optimization. We first discuss the architecture and components of Panorama system. We also discuss the schema integration in this system. And we extend our discussion to the query language, transaction management, and the query processing developed for this system. Finally, a conclusion and the future work for our designed system have been given.

Flexible Coordination in Virtual Enterprises

Flexible coordination is a major aspect in the development of open support infrastructures for Industrial Virtual Enterprises (VE). The coordination issues in VEs in the context of Small and Medium size Enterprises and the need for very flexible and easily configurable solutions are discussed. The approaches and the hierarchical coordination infrastructure being partly developed by and applied to the Esprit PRODNET II project is presented. The combination of a worldlow management approach for coordination with a distributed / federated database management system is introduced as the coordination kernel, and some implementation results presented.

Security issues for federated database systems

This paper describes security issues for federated database management systems set up for managing distributed, heterogeneous and autonomous multilevel databases. It builds on our previous work in multilevel secure distributed database management systems and on the results of others' work in federated database systems. In particular, we define a multilevel secure federated database system and discuss issues on heterogeneity, autonomy, security policy and architecture.

Federated database management system: Requirements, issues and solutions

The use of database management systems (DBMS) to replace conventional file processing systems has dramatically increased in the past years. Although the use of DBMSs overcomes many of the limitations of file processing systems, many important applications require access to and integration of information among several and often incompatible DBMSs. In this paper we discuss an approach, known as the federated database approach, that allows users and applications to access and manipulate data across several heterogeneous databases while maintaining their autonomy. We discuss the requirements and objectives of a federated database management system, and outline the major issues and challenges for building and using such a system. In particular, we address the design issues from three angles: transaction management, system architecture, and schema integration. Also, we present a five-step integration methodology followed by a comprehensive example to illustrate the concepts and techniques involved in this integration methodology.