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Introduction to MySQL
MySQL is an open-source RDBMS software which is available free of cost. It can run on all
operating systems, including Linux, Unix and Windows. It is popular for web-based applications
and online publishing. It uses a query language called SQL (Structured Query Language). SQL
is the standard language for managing relational databases and performing various operations
on the data in the tables. It would enable us to store, retrieve, and manipulate data in the form
of tables.
SQL is a high-level interactive language that allows users to specify what is required to be done
in the form of queries. Unlike other high-level languages, we do not need to specify how the SQL
operations are implemented.
i + TYPES OF SQL COMMANDS
SQL uses various commands to perform different operations on a database.
Data Definition Language (DDL)
A Data Definition Language or Data Description Language (DDL) is a standard for commands
that define the different structures in a database. DDL statements create, modify and remove
database objects such as tables, indexes and users. Common DDL statements are CREATE, ALTER,
TRUNCATE, RENAME and DROP.
Data Manipulation Language (DML)
A Data Manipulation language (DML) is a language that enables users to retrieve, update, insert
and delete data in a database. Common DML statements are SELECT, UPDATE, INSERT INTO and
DELETE.
Data Control Language (DCL)
A Data Control Language is a language that has various commands which are used to grant and
take back authority from any database user. Some DCL statements are Grant and Revoke.
Transaction Control Language (TCL)
A Transaction Control Language is a language that has various commands which are used to
manage transactions in the database. These are used to manage the changes made by DML-
statements. Some TCL statements are Commit, Savepoint and Rollback.
i + DATA TYPES IN SQL
A data type defines a sort of value that a column will contain. In a database table, every column
must have a name and data type.
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