This method combines both the feature of the sequential and random organizations. Records are accessed by using an index or a table. The index stores the address of each record corresponding to key number of the record. The records within the file are stored sequentially but directly accessed to individual records.
A indexed sequential access method (ISAM) consists of
- The main file storage
- A table to maintain the index
An example is illustrated. Using this table (or index, directory), we can find out the address of any record, given the key value. For example, the record with key equal to ‘00120’ has the address “1”.
