A data warehouse is a collection of data from different sources that supports analytical querying. A Bitmap Index (BI) allows fast access to individual attribute values that are needed to answer a query by representing the ...

The goal of on-line analytical processing (OLAP) is to quickly answer queries from large amounts of data residing in a data warehouse. Materialized view selection is an optimization problem encountered in OLAP systems. ...

MySQL is an OLTP system without the ability to handle SQL subqueries. As part of our project in query optimization , we add subquery processing to MySQL through rewriting. First, we incorporate the ability to handle ...

Several surveys indicate that a significant percentage of data warehouses fail to meet business objectives or are outright failures. One of the reasons for this is that requirement analysis is typically overlooked in real ...

Materialized views are nowadays commonly used in the data warehouse environment. Materialized views need to be updated when data sources change. Since the update of the views may impose a significant overhead, it is essential ...

Software design is a complex activity. A successful designer requires knowledge and training in specific design techniques combined with practical experience. Designing a dimensional model embodies this challenge. This ...

Current data warehouse and OLAP technologies can be applied to analyze the structured data that companies store in their databases. The circumstances that describe the context associated with these data can be found in ...

We address the inference control problem in data cubes with some data known to users through external knowledge. The goal of inference controls is to prevent exact values of sensitive data from being inferred through answers ...

BST Condensed Cube is a fully computed cube that condenses those tuples, which are aggregated from the same single base relation tuple, into one physical tuple. Although it has been proved to be an effective approach to ...