SQL Structured Query Language

SQL: Structured Query Language

SQL is used for storing, retrieving and manipulating (managing data) data in databases (MySql, Oracle, Sybase, MS Access). SQL is a query language, not a programming language. The SQL language is divided into queries, clauses and statements etc. It helps consumer (user) to describe and manipulate the data.

Importance

• SQL is used for the query, insert, collect and manages data from the database. It store and fetch data from database immediately.
• It helps to find the needed data (information) easily.
• You can easily write commands almost same as we write English as it is a query language not a programming language.
• Almost every database system needs SQL for processing.

Reasons to learn

• Easy to learn
• It doesn't require coding (SQL manages the database system by using standard SQL).
• You can run SQL on laptop, servers, e.t.c.
• SQL Standard (Databases are used by established standards. ANSI in 1986 and ISO in 1987).

SQL defines following ways to manipulate data stored in an database.

create (create new table or database)(DDL)
alter (for alteration)(DDL)
truncate (to delete data from table)(DDL)
drop (to drop a table)(DDL)
rename (to rename a table)(DDL)
insert (to insert a new row)(DML)
update (to update existing row)(DML)
delete (to delete a row)(DML)
merge (merging two rows or two table)(DML)

Terminology:

SQL: Structured Query Language
DDL: Data Definition Language
DML: Data Manipulation Language
TCL: Transaction Control Language
DCL: Data Control Language
RDBMS: Relational Database Management System
ANSI: American National Standards Institute
ISO: International Standards Organization