SQL Introduction - Structured Query Language for RDBMS
What is SQL?
- SQL is Structured Query Language used for creating, maintaining, retrieving and deleting data in Relational Database Management Systems(RDBMS).
- SQL language includes three languages
- Data Definition Language(DDL) - used to create and modify the structure of the relational database.
- Data Manipulating Language(DML) - used to perform the operation like select, insert, update and delete on the data in the relational database.
- Data Control Language(DCL) - used to aggregate and control the access of the data in the database.
- The database is a storage container. Database is used to organize the data with higher accuracy and lesser conflicts. SQL is mainly designed for the Relational Database Management System (RDBMS).
- Relational database stores the data in the form of relational tables. A database table consists of the number of rows and columns. Every table has a unique name. Each row refers to a tuple or record. Each column has a name that refers to a field or attribute. .
Why should we need SQL?
- SQL enables the user to retrieve the data from the Relational Database Management System(RDBMS).
- By using SQL, the users can create a table and database.
- Enable the users to define and describe the data in the database and manipulating those data in the database.
- With SQL, the users can easily insert the data into the database.
- With SQL, the users can update the tables in the database.
- With SQL, the users can easily create the views, stored procedures, and functions in the database.
- By using SQL, the users can set permissions on tables, procedures, and views.
- With SQL, the users can delete a data record from the table in the database. Also, users can easily drop the tables and databases.