View materialization is recognized to be one of the most effective ways to increase the Data Warehouse performance; nevertheless, due to the computational complexity of the techniques aimed at choosing the best set of views to be materialized, this task is mainly carried out manually when large workloads are involved. In this paper we propose a set of statistical indicators that can be used by ...

01 Chapter 1: Introduction 02 Chapter 2: An Overview of Query Processing 04 Chapter 3: DDAG 08 Chapter 4: Distributed Query Optimization 10 Chapter 5: View Materialization using DDAG 11 Chapter 6: View Replacement 16 Chapter 7: Results 17 Chapter 8: Conclusion and Future Work 19 References 20

A global Data warehouse (DW) integrates data from multiple distributed heterogeneous databases and other information sources. A global DW can be abstractly seen as a set of materialized views. The selection of views for materialization in a DW is an important decision in the implementation of a DW. Current commercial products do not provide tools for automatic DW design. In this paper we provid...

Querying large datasets distributed over thousands of endsystems is a challenge for existing distributed querying infrastructures. High data availability requires either replicating or centralizing the dataset but both require infeasibly high network bandwidth. In-situ querying provides low bandwidth overheads but requires users to tolerate low data availability. This paper advocates partial da...

We investigate the experimental effectiveness of XML security views. Our model consists of access control policies specified over DTDs with XPath expression for datadependent access control policies. We provide the notion of security views for characterizing information accessible to authorized users. This is a transformed (sanitized) DTD schema that is used by users for query formulation. To a...

Today, network intrusion detection systems (NIDSs) use custom solutions to log historical network flows and support forensic analysis by network administrators. These solutions are expensive, inefficient, and lack flexibility. In this paper, we investigate database support for interactive network forensic analysis. We show that an “out-of-the-box” relational database management system (RDBMS) c...

In many design applications, it is common practice to store complex hierarchical objects in a compact folded form to save storage space and to reduce processing costs for accessing the objects. In these folded representations, complex objects are built up from identical and otherwise indistinguishable design objects. However, it is often necessary, especially during the refinement of data, to d...

Quick response time and accuracy are important factors in the success of any database. In large databases particularly in distributed database, query response time plays an important role as timely access to information and it is the basic requirement of successful business application. A data warehouse uses multiple materialized views to efficiently process a given set of queries. The material...

Queries to data warehouses often involve hundreds of complex aggregations over large volumes of data, and so it is infeasible to compute these queries by scanning the data sources each time. Data warehouses therefore build a large number of materialized views to increase system performance. However, materialized views need to be immediately updated when its sources are changed, leading to a pos...