File Organization

The arrangement of records in a file is known as file organization. File organization deals with the arrangement of data items in the secondary storage devices like magentic disk. i.e. the file organization deals with how the logical tuples(rows) of tables(relations) are organized on the physical storage medium.

Depending on the above considerations a file may be organized as:
1. Serial file
2. Sequential file
3. Direct or random access file
4. Indexed sequential file

Serial file - In a serial file the records are placed one after the other. However, there is no specific order in the arrangement of these records. Serial files are ill-suited for many applications. They are usually created as temporary files and then sorted in some sequence before being processed.

Sequential files - A sequential file is a file in which the records are sorted in some order, say the student file student file contains records of students in the ascending order of roll number of students.

Direct access files - In random access or direct access method of file organization each record has its own address on the file. With the help of this physical address, the record can be directly accessed for reading or writing.