Concurrency control techniques for a multimedia database system

The paper presents the concurrency control methods used to provide simultaneous access to databases, in a multimedia relational database management system. This is an original system that integrates methods for extracting visual characteristics (color and texture characteristics) from images and for executing content-based visual queries. In order to accomplish this, it was defined an original new data type called IMAGE. This data type is used to store the images along with the characteristics extracted and other important information. The problems that should be handled refers to process multiple requests and access the same set of data in a concurrent environment. The databases must be protected with a synchronization algorithm to ensure that the information doesn´t get corrupted when multiple clients´ requests access concurrently the same set of data.