SQL is an inclusive language for interacting and controlling
the DBMS or database management system which contains all about forty statements,
specialized in database management works. It is a descriptive or declarative language
instead of procedural one (Fourth generation language).
Structured English Query Language is its original name
provided by IBM, shortened to the acronym SEQUEL. When IBM was discovered that
SEQUEL has a trademark owned by the Hawker Suddenly Aircraft Company of the United Kingdom,
they shortened the acronym to SQL. The word “English” was then dropped from the
spelled-out name to match the new ellipsis.
SQL is used to manage all of the methods that a DBMS
provides for its developers, including:
Data definition
SQL lets a user describe the configuration and business of the stored data
and relationships among the stored data items.
Data retrieval
SQL allows a user or a function program to recover stored records from the
database and use it.
Data
manipulation SQL allows a user or an application software project to update
the database by adding new records, removing old records, and modifying
previously stored records.
Access control
SQL can be used to restrict a user’s capability to recover, add, and modify
record, protecting stored record against unauthorized access.
Data sharing
SQL is used to coordinate record sharing by concurrent clients, ensuring
that changes made by one client do not inadvertently wipe out changes made at
nearly the same time by another client.
Data integrity
SQL describes integrity constraints in the database, protecting it from
corruption due to inconsistent updates or structure failures.
SQL plays following roles also:
SQL equal to an
interactive query language: clients type SQL commands into an interactive
SQL program to retrieve record and display it on the screen, providing a
convenient, easy-to-use tool for ad hoc database queries.
SQL equal to
database programming language: Programmers embed SQL commands into their
application programs to entrance the record in a database. Both client-written
programs and database utility programs (such as report writers and records
entry tools) use this technique for database right of entry.
SQL like a
database administration language: The database administrator answerable for
managing a mainframe or minicomputer database uses SQL to define the database
structure and to manage access to the stored record.
SQL like a
client/server language: PC programs
use SQL to communicate over a network with database servers that store shared record.
This client/server architecture is used by many trendy enterprise-class
applications.
SQL like an Internet
data access language: Internet web servers that interact with business record
and Internet application servers all use SQL as a standard language for
accessing corporate databases, often by embedding SQL database access within
popular scripting languages like PHP or Perl.
SQL like a
distributed database language: Distributed database management systems use
SQL to help distribute data across many connected computer systems. The DBMS
software on each system uses SQL to communicate with the other systems, sending
requests for data access.
SQL like a
database gateway language: In a computer network with a mix of different
DBMS products, SQL is often used in a gateway that allows one brand of DBMS to
communicate with another brand.
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