Persistence - Definition and Overview

Persistence is the term used in computer science to describe a capability used by a computer programmer to store data structures in non-volatile storage such as a file system or a relational database.

Without this capability data structures only exist in-memory, and will be lost when a program exits. Persistence allows, for example, a program to be restarted and re-loaded with the data structures from a previous invocation of the program.

Design patterns solving this problem are container based persistence, component based persistence and the Data Access Object model.

Examples of persistence are using Java serialization to store Java objects on disk or using J2EE to store Enterprise Java Beans in a relational database.

Persistence also refers to the ability to retain previous versions of a data structure after it is modified; see persistent data structure.

Persistence is also used to describe how long a CRT's phosphor remains lit after it has been struck by the CRT's electron gun.