In this post, we will discuss about different types of SQL statements and SQL Questions for Beginners frequently asked during testing interviews.
What is SQL?
SQL is an acronym for Structured Query Language. It is a structured query language for Relational Database Management Systems (RDBMS). It is a data language for creating/manipulating/processing data & metadata in a database.
SQL can be classified into following:
What are the types of SQL Statements?
1.Data Definition Language(DDL)
2.Data Manipulation Language(DML)
3.Data Query Language (DQL)
4.Data Control Language(DCL)
5.Transition Control Language(TCL)
What is DQL?
DQL full form is Data Query Language. It deals with SELECT statements. A SQL SELECT statement allows you to retrieve records from one or more tables in the database.
ex: SELECT * FROM emp ;
What is DDL?
DDL full form is Data Definition Language. It deals with with creation and alteration of database objects like tables, views in the database.
ex: CREATE TABLE , ALTER TABLE , DROP TABLE.
What is DML?
DML full form is Data Manipulation Language. It deals with querying, updating, deleting and inserting records in tables and views in the database.
ex: INSERT , UPDATE , DELETE.
What is DCL?
DCL full form is Data Control Language. It deals with enforcement of database security in a multi-user environment.These are issued by Database Administrators or owners of the database object.
Ex:GRANT , REVOKE.
What is TCL?
TCL full form is Transactional Control Language. Transaction Control statements deals with managing changes made by DML statements.
ex: COMMIT , ROLLBACK , SAVEPOINT.