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WEEK 2
CLASS: SS 2
TOPIC: File Organization
CONTENT:
- Comparison of the Three file organization
SUB-TOPIC 1:
FILE ORGANIZATION
File organization is a way of organizing the data or records in a file. It does not refer to how files are organized in folders, but how the contents of a file are added and accessed.
Is also a systematical way of arranging record in a file that is stored on a disk. You can access a file of record in different ways and tailor it in a variety of ways.
TYPES OF FILE ORGANIZATION
There are a large number of ways records can be organized on disk or tape. The main methods of file organization used for files are;
- Heap File Organization
- Sequential File Organization
- Hash / Direct File Organization
- Cluster File Organization
- Indexed Sequential Access Methods (ISAM)
Heap File Organization
An unordered file, sometimes called a heap file, is the simplest type of file organization.
Records are placed in file in the same order as they are inserted. A new record is inserted in the last page of the file; if there is insufficient space in the last page, a new page is added to the file. This makes insertion very efficient. However, as a heap file has no particular ordering with respect to field values, a linear search must be performed to access a record. A linear search involves reading pages from the file until the required is found.
Sequential File Organization:
In a sequential file organization, records are organized in the sequence by which they were added. You cannot insert a new record between existing records, but only at the end of the last record. It is a simple file organization that allows you to process batches of records in the file without adding or deleting anything. However, to access a particular record, processing must run through all the other records above it because it does not generate any random key to identify the location of the record.
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