The term 'file organization' has often been a source of confusion for computer users. Although some believe that this particular concept is related to the methods in which files are organized within folders, this is not quite accurate. In fact, file organization is used to describe how the specific data within a file is incorporated into it and accessed as needed.
Although various types of file organization are currently in use, some of the most popular are sequential, indexed and relative organization. Understanding how these methods of organization function, and how they relate to one another, can help you better appreciate the unique actions at play inside of your computer that occur on a daily basis. File organization is, by any standard of measure, an integral part of your computer's operation.
File Structure and Organization: Sequential
As mentioned previously, the three most common methods of file organization include sequential, indexed and relative organization. Sequential organization describes a method in which specific data records are organized in the exact order in which they have been added to the computer. Although this method of organization has the benefit of added clarity, it also has its own unique restrictions. For example, new records cannot be added within a batch of pre-existing records. Instead, a record must be added at the end of the most recent record entry.
Relative File Organization
In a relative organization system, each particular record is assigned a key, which is a numeric indicator that can be used to identify a particular record and access it at any given time. In a relative organization system, records can be re-arranged as needed without any requirements related to the date they were added or their particular file size. Using the relative numerical key assigned to a record, specific entries can be accessed without requiring them to be arranged in any specific order. It is important to note, however, that relative organization uses a system of key identifiers which describe an items position to others in the organization. When accessing an item, its key may change depending upon where it is located relative to other items.
Evaluating Indexed Organization
Unlike relative organization, the keys provided to records in an indexed organization are fixed and unique, without regard to any pre-existing order. Although indexed organization systems do provide the greatest degree of flexibility, they also present the greatest programming challenges for developers. With that in mind, it could be argued that the indexed organization method requires the greatest amount of effort in order to set up successfully.