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Exposure to Computer Disciplines



                   Notes         Introduction

                                 All of us are familiar with the term data. In fact, unknowingly we come across data in our day-
                                 to-day life everyday. The age of a person, price of potato, number of students in a school, pin
                                 code of a city, etc. are some examples of data. In our life we have to remember so much of data.
                                 But it is easier for us to remember all information for a few individuals. For example, you may
                                 be in a position to tell accurately the age, height, complexion, income, educational qualification,
                                 residential address, etc. of your close friends. But it is too difficult for you to memorise all these
                                 information for a large number of individuals. Let us consider the example of National Open
                                 School (NOS). Every year about one lakh students take admission in NOS. If you are asked to
                                 memorise records of date of birth, subjects offered and postal address of all these students, it will
                                 not be possible for you.
                                 To deal with such problems we construct a database. We arrange all information about students
                                 in a tabular form. We keep all the records so that if I am asked, ‘How many students are there in
                                 Economics?’ I am in a position to answer.

                                 8.1 Database

                                 A database is a system intended to organize, store, and retrieve large amounts of data easily. It
                                 consists of an organized collection of data for one or more uses, typically in digital form. One
                                 way of classifying databases involves the type of their contents, for example: bibliographic,
                                 document-text, statistical. Digital databases are managed using database management systems,
                                 which store database contents, allowing data creation and maintenance, and search and other
                                 access.

                                 A database is a collection of information that is organized so that it can easily be accessed, managed,
                                 and updated. In one view, databases can be classified according to types of content: bibliographic,
                                 full-text, numeric, and images.

                                 In computing, databases are sometimes classified according to their organizational approach.
                                 The most prevalent approach is the relational database, a tabular database in which data is
                                 defined so that it can be reorganized and accessed in a number of different ways. A distributed
                                 database is one that can be dispersed or replicated among different points in a network. An
                                 object-oriented programming database is one that is congruent with the data defined in object
                                 classes and subclasses.
                                 Computer databases typically contain aggregations of data records or files, such as sales
                                 transactions, product catalogs and inventories, and customer profiles. Typically, a database
                                 manager provides users the capabilities of controlling read/write access, specifying report
                                 generation, and analyzing usage. Databases and database managers are prevalent in large
                                 mainframe systems, but are also present in smaller distributed workstation and mid-range
                                 systems such as the AS/400 and on personal computers. SQL (Structured Query Language)
                                 is a standard language for making interactive queries from and updating a database such as
                                 IBM’s DB2, Microsoft’s Access, and database products from Oracle, Sybase, and Computer
                                 Associates.










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