DBMS Lecture 29
BCA II
Sql Commands
Structured Query Language (SQL) as we all know is the database language by the
use of which we can perform certain operations on the existing database and also we
can use this language to create a database.
The standard SQL commands to interact with relational databases are CREATE,
SELECT, INSERT, UPDATE, DELETE and DROP. These commands can be classified
into groups based on their nature:
These SQL commands are mainly categorized into four categories as:
1. DDL – Data Definition Language
2. DML – Data Manipulation Language
3. DCL – Data Control Language
4. DQL – Data Query Language
Neelam Sunda, Assistant Professor, KMM JaipurPage 1
DBMS Lecture 29
BCA II
DDL -Data Definition Language:
DDL or Data Definition Language actually consists of the SQL commands that can be
used to define the database schema. It is used for creating tables, schema, indexes,
constraints etc. in database. Let’s see the operations that we can perform on database
using DDL:
Command Description
Creates a new table, a view
CREATE of a table, or other object in
database
Modifies an existing
ALTER database object, such as a
table.
Deletes an entire table, a
DROP view of a table or other
object in the database.
Remove all records from a table,
TRUNCATE including all spaces allocated
for the records are removed.
Rename an object existing in
RENAME
the database.
Add comments to the data
COMMENT
dictionary.
Neelam Sunda, Assistant Professor, KMM JaipurPage 2
DBMS Lecture 29
BCA II
DML -Data Manipulation Language:
The SQL commands that deals with the manipulation of data present in the database
belong to DML or Data Manipulation Language and this includes most of the SQL
statements.
Command
Description
INSERT
Creates a record
UPDATE
Modifies records
DELETE
Deletes records
DCL -Data Control Language:
DCL includes commands such as GRANT and REVOKE which mainly deals with the
rights, permissions and other controls of the database system.
Command Description
GRANT Gives a privilege to user
REVOKE Takes back privileges granted
from user
DQL -Data Query Language:
Command Description
SELECT Retrieves certain records from one
or more tables
Neelam Sunda, Assistant Professor, KMM JaipurPage 3
DBMS Lecture 29
BCA II
TCL –Transaction Control Language:
TCL commands deals with the transaction within the database.
Command Description
COMMIT
Commits a Transaction
Rollbacks a transaction in case
ROLLBACK
of any error occurs
Sets a save point within a
SAVEPOINT
transaction
Specify characteristics for the
SET TRANSACTION
transaction
References:
TUTORIALS POINT Simply Easy Learning pdf from tutorialspoint.com
https://www.geeksforgeeks.org/sql-ddl-dql-dml-dcl-tcl-commands/
https://beginnersbook.com/2015/04/dbms-languages/
Neelam Sunda, Assistant Professor, KMM JaipurPage 4
DBMS Lecture 29
BCA II
Neelam Sunda, Assistant Professor, KMM JaipurPage 5
