DBMS_SHORT

DBMS /SQL Interview Questions

1) What is sql ?

Structer Query language is a computer language for Management of database and data manipluation . SQL is used to query ,insert,update and modify datain a database.
it contains a lot of component which a user can execute to perform operation on a database.

2.how many component of DBMS

component of sql /database language is:-
1.DDL
2.DML
3.DCL
4.DQL

3) What is query create?

create statement is used to created database schema and to define the type and structer of the data to be strored in the database.
Create statement can be used for:-
Creating a Database
Creating a Table

4) What is the difference between the truncate and drop query in SQL?

drop query	Truncate query
Drop Table does delete complete table but it delete table structure too.	Truncate Table doesn't delete the structer of the table.

5) What is Alter query ?

Alter is used to modify the structer of the rxisting table. it is used to add,delete,modify,or rename column in the existing table. It is used to add and drop various constrains on an existing table.

Alter table -Add column = for adding new column in a table.
Alter table -Drop column = for removing existing column in table.
Alter table -Modify column = To Modify existing column in a table.
Alter table -Rename column = To rename an existing column in a table.

6) What is Drop query ?

Drop-table statement completely removes a table from the database. this command will destroy the table structer and the data stroedin it.
Drop Table table-name.

7). What is truncate query?

Truncate statement is used to remove all rows (complete data) from a table .it is similar to the delete statement with no WHERE clause.
Syntax:-
Truncate table table_name;