Traditional File Systems
File-based systems were an early attempt to computerize the manual filing system. File-based system is a collection of application programs that perform services for the end-users, such as updating, insertion, deletion adding new files to database etc. Each program defines and manages its data.
When a computer user wants to store data electronically they must do so by placing data in files. Files are stored in specific locations on the hard disk (directories). The user can create new files to place data in, delete a file that contains data, rename the file, etc which is known as file management; a function provided by the Operating System (OS).
Database Management System
The improvement of the File-Based System (FBS) was the Database Management System (DBMS) which came up in the 60’s. (DBMS) consists of software that operates databases, providing storage, access, security, backup and other facilities. This system can be categorized according to the database model and the type of computer that they support such as a server cluster or a mobile phone, the query language(s) that access the database, such as SQL or XQuery, performance trade-offs, such as maximum scale or maximum speed or others. Some DBMS cover more than one entry in these categories, e.g., supporting multiple query languages. Meanwhile database management systems are usually accessed in a client-server manner, where the database client and the server are located on different machines (in a local area network).
The Database Management System removed the trouble of manually locating data, and having to go through it. The user could create a suitable structure for the data beforehand, to place the information in the database that the DBMS is managing. Hence, the physical organizing of files is done away with and provides the user with a logical view of the data input.
A database is a collection of interrelated information stored in a database server; these data will be stored in the form of tables. The primary aim of database is to provide a way to store and retrieve database information fast and in an efficient manner.
The Difference between TFS and DBMS
There are number of characteristics that differ from traditional file management system to database management system. In file system approach, each user implements the required files for a specific application to run. (Example: in a sales department of an enterprise, one user will be maintaining the details of the number of sales personnel in that department and their grades. These details will be stored and maintained in a separate file. Another user will maintain the salary details of these sales personnel and the detailed salary report will be stored and maintained in a separate file. Although both of the users need the data of the salespersons, they will be having their details in separate files and they need different programs to operate their files.) When such data is isolated in separate files, it is difficult to access data that should be available for both users. This will lead to wastage of space and redundancy or replication of data, which may lead to confusion, as sharing of data among various users is not possible and data inconsistency may occur. These files will not be having any inter-relationship among the data stored in these files. Therefore in traditional file processing every user will be defining their own constraints and implement the files according to their needs.
In database approach, a single store of data is maintained that is defined once and then accessed by many users, as database belongs to the entire organization and can be shared by all authorized users. The essential characteristic of database approach is that the database system not only contains data but it contains complete definition or description of the database structure and control. These definitions are stored in a system catalog, which contains the information about the structure and definitions of the database. The information stored in the catalog is called the metadata, it describes the primary database. Hence this approach will work on any type of database for example, insurance database, Airlines, banking database, Finance details, and Enterprise information database. But in traditional file processing system the application is developed for a specific purpose and they will access specific database only. But the processing speed in TFS is high compared to DBMS.
The other main characteristic of the database is that it will allow multiple users to access the database at the same time and sharing of data is possible. The database must include concurrency control software to ensure that several users trying to update the same data at the same time, it should maintain in a controlled manner. In file system approach many programmers will be creating files over a long period and various files have different format, in various application languages, where duplication of data can occur.
This redundancy in storing same data multiple times leads to higher costs and wastage of space. This may result in data inconsistency in the application; this is because update is done to some of the files only and not all of the files. Moreover in database approach multiple views can be created;
- External view – User/Application view,
- Conceptual view – Logical view,
- Internal view – Details about the structure of data and physical storage of information.
View is a tailored representation of information contained in one or more tables. View is also called as “Virtual table” because view does not contain physically stored records and will not occupy any space.
A multi-user database whose users have variety of applications must provide facilities for defining multiple views. In traditional file system, if any changes are made to the structure of the files it will affect all the programs. Therefore, changes to the structure of a file will require to change all programs that access the file and whereby data dependence will be lost. But in the case of database approach the structure of the database is stored separately in the system catalog from the access of the application programs. This property is known as program-data independence.
Database can also be used for continuous storage for program objects and data structures that resulted in object oriented database approach. Traditional systems suffered from impedance mismatch problem and difficulty in accessing the data, which is avoided in object oriented database system. Database can be used to represent complex relationships among data as well as to retrieve and update related data easily and efficiently. Hence DBMS does not automatically remove redundancies, but help to control redundancy.
It is possible to define and enforce integrity constraints for the data stored in the database. The database also provides facilities for recovering hardware and software failures, as it has automatic and intelligent backup and recovery procedures. It reduces the application development time considerably when compared to the file system approach and availability of up-to-date information of all the users. It also provides security to the data stored in the database system and maintains integrity.
A highly technical person will be required to handle the database, while for TFS, it is not so.
File-based systems are very dependent upon the application programmer. Any required queries or reports have to be written by the application programmer. Normally, a fixed format query or report can only be entertained and no facility for ad-hoc queries if offered. DBMS has data independence. The way information is stored and the way information issued is independent of each other.
File-based systems also give tremendous pressure on data processing staff, with users’ complaints on programs that are inadequate or inefficient in meeting their demands. Documentation may be limited and maintenance of the system is difficult. Provision for security, integrity and recovery capability is very limited. Whereas, DBMS has control over security as it provides tools such as use of User Code, Password / Privileges and Roles to ensure security of data.