Concurrent Use and Security

A database can be a common resource for many users. Multiple users can query and modify a database simultaneously. The database server (the program that manages the contents of all databases) ensures that the queries and modifications are done in sequence and without conflict.

Having concurrent users on a database provides great advantages but also introduces new problems of security and privacy. Some databases are private; individuals set them up for their own use. Other databases contain confidential material that must be shared, but only among a select group; still other databases provide public access.