What Is sarkari Yojna
We live in the age of information technology. The explosive growth of computer usage during the last twenty years is unrivalled by any other type of human expansion in recorded history. From times immemorial, when the mankind had its existence, the data is being used, the data which is collection of raw facts, figures etc. is used at every instance of time, one way or the other. To use this data, it has to be processed, so that we can derive meaningful conclusions. This processed data is known as information.
The data has to be stored, retrieved, modified and maintained. Traditionally, the data was maintained manually, stored in fields, updated and retrieved as and when required. This causes a lot of problems like volume of data, storage, access etc. which are reduced to a great extent due to use of computer. Traditionally, data is maintained as collection of records i.e. Files.
The data has to be stored, retrieved, modified and maintained. Traditionally, the data was maintained manually, stored in fields, updated and retrieved as and when required. This causes a lot of problems like volume of data, storage, access etc. which are reduced to a great extent due to use of computer. Traditionally, data is maintained as collection of records i.e. Files.
These files are collection of related data and records. Database is the collection of interrelated data i.e. It is composed of a collection of files that are linked in such a way that information from one of the files may be combined with information from other files so that a user may receive the exact information needed. e.g. Consider the names,telephone numbers and adress of People You Know This Is A Collection Of Related Data And Hence Database.
A database may be defined as a collection of interrelated data stored together without harmful or unnecessary redundancy to serve multiple applications. The database is owned by a single user but shared by many users. A database has following implicit properties:
1. A database represents some aspect of real world called the mini world. Changes to the mini world are reflected in database.
2. A database is designed, built with data for a specific purpose. It has an intended group of users.
3. A database is a logically coherent collection of data with some inherent meaning. In other words, a database has some source from which data are derived, some degree of interaction with events in the real world and an audience that is interested in the contents of database. A database can be of any size and of varying complexity.
It is managed by an individual (or group) called the Database Administrator (DBA), who is responsible for designing, creating and maintaining the database to satisfy the needs of users. All access to the database is controlled by a sophisticated software package called Database Management rocessed in Systems (DBMS). DBMS is the collection of interrelated data and a set of procedures to access that data.
It has programs to set the storage structures, load the data, accept data requests from programs and user, format retrieved data so that it appears in a form the program or user expects, hide data that a particular user should not have access to, accept and perform updates, allow concurrent use of the data without having User's interface with each other, and perform backup and recovery procedures automatically ? Let us Some of the more popular relational database management systems include:
Components of Database System
A Database management system is a collection of interrelated data and a set of programs to data. The collection of data is called database, which contains information relevant to an enterprise goal of DBMS is to provide a way to store and retrieve database information that is both con efficient. Figure 3.1 shows a database system.
The database systems har four components Data, Hardware, Software and Users. Data Data refers to collection of related information, combined to be stored at a central place. which is the basis of any activity in the organization.
It is that component, for whose management the DAMS works. It is the most important and essential component and is the core of any organization and its (0) Handware The hardware components of the system consist of (4)
The secondary storage devices such as magnetic tapos, Hard duk, CD ROM, DVD ROM. which are used to hold large volumes of data, together with associated I/O devices, device controller. 10 channels and so on. (4)
The hardware processor and associated main memory that are used to support the execution the database system software of (a) Software Between the physical database itself is the data as physically stored and the users of the tem, is a layer of software, known as Database Manager or Database Management System (DBMS). All pests for access to database are handled by the DBMS.
Girl Users: This component includes all type of users, who derive the benefit of getting their work done by the DBMS, so that they have the required data and information with them for decision making Users are of four types
1. Application programmers or Ordinary users
3. Database Administrator (DBA)
1. Application programmers or Ordinary users These users write application programs to interact with the database. Application programs can be written in some programming language such as C, C++, JAVA. Visual Basic or some higher level fourth generation language. Such programs access the database by issuing the appropriate request, typically a SQL statement to DBMS.
2. End users End users are the users, who use the applications developed. End users need not know ahout the working database design, the access mechanism etc. They just use the system to get their task done. End users are of two types:
(a) Direct users (6) Indirect users, G) Direct users Direct users are the users who use the computer, database system directly, by following instructions provided in the user interface eg. People at railway reservation counters, who directly interact with database. (6) Indirect users: Indirect users are those users, who desire benefit from the working of DBMS indirectly. They use the outputs generated by the programs, for decision making or any other purpose.
They are just concerned with the outpur and are not bothered about the programming part. 3. Database Administrator (DBA): Database Administrator (DBA) is the person who makes the strategic and pelcy decisions regarding the data of the enterprise, and who provides the necessary technical support for implementing ther decins Therefore.
DBA is responsible for overall control of the system at a technical level. 4. System Analyst System analysts determine the requirement of end users, especially naive and parametric ndum, and develop specifications for transactions that meet these requirements
Advantages of a Database System
1. Minimal Redundancy: In a file system, each application has its own private files. This can often lead to considerable redundancy (duplication) in stored data, with resultant wastage in storage space. For example, a personnel application and an education records application may each own a file containing department information for employees. These two files can be integrated, and redundancy can be eliminated.
2. Inconsistency can be avoided : In case the system is not aware of the duplication (i.e. the redundancy is not controlled), there will be occasions when the two entries will not agree (i.e. when only one record is updated). At such times, the database is said to be inconsistent. A database that is in an inconsistent state is
3. Sharing of data: It means not only that existing applications can share the data in the database, but also that new applications can be developed to operate against that same stored data.
4. Standard can be enforced: With central control of the database, the DBA can ensure that all applicable standards are followed in the representation of the data such as format of data items, conventions on data names, documentation standards etc. which will result in uniformity of the entire database as well as its usage.
5. Search capability: The user of database may ask a wide variety of the questions about the data. If a quick answer is needed at a terminal, the search will have to be fast and the capability to search a database quickly with different search criteria is highly dependent on the physical data organization.
6. Integrity: By integrity, we mean unification of several files into one file. When a database contains data employed by a number of different users, it is important that the data items and associations between dara items may not be destroyed. This integration reduces redundancy and also eliminates inconsistency.
7. Privacy and Security: Data security refers to protection of data against accidents or intentional disclosure to unauthorized persons. Privacy refers to the rights of individuals and organizations to determine for themselves when, how and to what extent information about them is to be transmitted to other.
Disadvantages of Database System
1. DBMS software is very costly
2. High Hardware Cost: Additional memory and processing power may be required to run the DBMS, resulting in the need to upgrade the hardware.
3. High Conversion Cont The organization that was using file system needs to load files into the database which may be a difficult and time consuming process.
4. Higher Programming Cost: Because a DBMS is a complex tool with many features, it requires experienced programmers resulting in extra payment for hire and expertise.
5. Backup and Recovery are more difficult This is because of increased complexity and because databases are often processed by several users concurrently.