What criteria should be adopted for choosing type of file organization.
Selecting a file organization is a design decision; therefore it must be done having in mind the achievement of excellent performance regarding the most as usage of the file. The criteria generally considered significant are:
1. Fast access to particular record or collection of associated records
2. Simple record update, adding or removal, without disrupting here 1
3. Storage efficiency
4. Redundancy like a warranty against data corruption.
Needless to say, such requirements are in contrast along with each other for all however the most trivial situations and the designer job of this, to get a good compromise among them, yielding a sufficient solution to the problem at hand. For illustration, easiness of adding/ etc. is not a matter when explaining the data organization of CD ROM product, while fast access is specified the huge amount of data that such media can store. Although as this will become apparent shortly, fast access techniques are based upon the use additional information concerning the records, that in turn competes with the high volumes of data to be stored.
Logical data Organization is certainly the subject of whole shelves of books into the "Database" section of your library. At this time we'll briefly address several of the simpler used techniques, mostly due to their relevance to data management from the lower-level (regarding a database's) point of view of an OS. 5 organization models will be seems as:
(i) Pile.
(ii) Sequential.
(iii) indexed-sequential.
(iv)Indexed
(v) Hashed.