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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.
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
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This document was uploaded on 04/07/2014.
- Spring '14