Definition: ISAM is short for Indexed Sequential Access Method, a method for indexing data for fast retrieval both directly (i.e. random access) or sequentially. It is often used in implementing relational databases with additional logic to manage the relations between tables such as in SQL Server.
ISAM is a simple method where the data is stored sequentially in records that are all the same size (fixed length). Indexes are kept in a separate table pointing to the indexed rows. For single user databases this is very fast, and only when multi-user access is required is extra code needed for handling multiple updates. One way round this is to make it accessible via a client to a server where multiple updates can be correctly handled through mechanisms such as record or table locking.
Glossary:
A B C D E F G H I J K L M N O P Q R S T U V W X Y ZExamples:
Dbase is an example of an ISAM based database.
