Large databases on large computer systems are

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Unformatted text preview: n from the data stored in the database, this approach can be very inefficient and frustrating when there are thousands of records and several files in the database. Hence all database management systems provide a query language that enables users to define their requirements for extracting the desired information from the database in the form of queries. For example, from an inventory database, a user may be interested in such information as "list out the item description and vendor name for all items whose current inventory level is less than 20 units" or "list out the stock number and item description for all items with a profit margin greater than 25%". Earlier each database management system had its own query language. The main problem with this was that queries developed for one DBMS could not be used with other DBMSs. However, eventually one query language, called SQL (pronounced "S-Q-L"), emerged as an industry standard. It was originally developed by IBM and was based on an earlier query language called SEQUEL. SEQUEL being an acronym for "Structured English QUEry Language", many people pronounce SQL as "Sequel" and believe that it stands for "Structured Query Langauge". However, SQL does not stand for anything. Today, SQL is the standard query language used in many DBMSs. A query language can be easily learnt by a non-programmer. This enables normal users of a database to access the database for desired information without the help of any programmer. Report Generator A report is the presentation of information extracted from a database. The report generator enables the users of a database to design the layout of a report so that it can be presented in the desired format. This means that the user can specify proper spacing between the data items to be presented in a report, and can also include suitable report titles and subtitles, column heading, page numbers, separation lines, and other elements that make a report more readable and presentable. The report gen...
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This document was uploaded on 04/07/2014.

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