Database systems isimli kitaptan önemli olarak gördüğüm alttaki kısmı yayınlamak istiyorum. Dosya-tabanlı yaklaşımın sınırlarını çizen, eksikliklerini az çok bize anlatabilecek bir yazı olduğunu düşünüyorum.
Limitations of the File-Based Approach
-Seperation and isolation of data : When data is isolated in seperate files, it is more difficult to access data that should be available.
-Duplication of data : Due to the decentralized approach taken by each department, the file based approach encouraged, if not necessitated, the uncontrolled duplication of data. Duplication is wasteful. It cost time and money to enter the data more than once. Perhaps more important, duplication can lead to loss of data integrity; in other words, the data is no longer consistent.
-Data dependence : The physical structure and storage of the data files and records are defined in the application code. This means that changes to an existing structure are difficult. This is known as program-data dependence
-Incompatibility of files : As the structure of files is embedded in the application programs, the structures are dependent on the application programming language. The direct incompatibility of such files makes them difficult to process jointly. This can be time-consuming and expensive
-Fixed queries/proliferation of application programs : From the end-user's point of a view, file-based systems proved to be a great improvement over manual systems. Consequently, the requirement for new or modified queries grew. However, file-based systems are very dependent upon the application programmer. Any queries or reports that are required have to be written by the application programmer.
Kaynak : Database Systems A practical approach to design, implementation and management, 2th edition