Data Models, Queries, Evaluation

Propositional Databases

Relational Databases

Constraint Databases

Temporal Databases

Geographic Databases

Moving Objects Databases

Image Databases

Constraint Objects Databases

Genome Databases

Set Databases

Constraint Deductive Databases

The MLPQ System

The DISCO System

Database Design

Interoperability

Data Integration

Interpolation and Approximation

Prediction and Data Mining

Indexing

Data Visualization

Safe Query Languages

Evaluation of Queries

Implementation Methods

Computational Complexity

Software Verification

Introduced forty years ago, relational databases proved unusually succe- ful and durable. However, relational database systems were not designed for modern applications and computers. As a result, specialized database systems now proliferate trying to capture various pieces of the database market. Database research is pulled into di?erent directions, and speci- ized database conferences are created. Yet the current chaos in databases is likely only temporary because every technology, including databases, becomes standardized over time. The history of databases shows periods of chaos followed by periods of dominant technologies. For example, in the early days of computing, users stored their data in text ?les in any format and organization they wanted. These early days were followed by information retrieval systems, which required some structure for text documents, such as a title, authors, and a publisher. The information retrieval systems were followed by database systems, which added even more structure to the data and made querying easier. In the late 1990s, the emergence of the Internet brought a period of relative chaos and interest in unstructured and "semistructured data" as it wasenvisionedthateverywebpagewouldbelikeapageinabook.However, with the growing maturity of the Internet, the interest in structured data was regained because the most popular websites are, in fact, based on databases. The question is not whether future data stores need structure but what structure they need.