What is Data Definition language and Data Manipulation language in DBMS | DDL and DML

Types of SQL Language 

What is Data Definition language?

DDL is used to build/ modify the structure of a database.

Commands included in DDL are :

1. create
2. alter 
3. drop
4. truncate

 CREATE A DATABASE
Create database dbname; 

DROP DATABASE
drop database dbname;

CREATING TABLE
create table tablename (col1 datatype primary key not null, col2 datatype not null);
or
create table tablename (col1 datatype not null, col2 datatype not null, primary key(col1));

DROPPING TABLE
drop table tablename;

ADDING NEW COLUMN

alter table tablename add column datatype;

DROPPING COLUMN

alter table tablename drop column columnname;

TRUNCATE TABLE

truncate table tablename;

What is Data Manipulation language?

1. DML is used to manipulate the data present in the tables.

2. DML includes

•  retrieval of information.
• insertion of new information.
• Updation of information
• Deletion of existing information.

3. DML is of 2 types:

• Procedural - user specifies what the data is and how to get the data
• Non Procedural  -  user specifies what the data is but does not specify how to get the data.

4. Commands included in DML are :

1. select
2. insert
3. update 
4. delete

DISPLAYING ALL COLUMNS OF TABLE
select * from tablename;

INSERTING VALUES IN TABLE
insert into tablename (col1 int, col2 varchar(20), col3 real, col4 date) values (1, 'any text', 32, 200.00,'2001-07013')

UPDATING TABBLE
update tablename set col1 = val1, col2= val2 where condition;

DELETE QUERY
delete from tablename where condition;

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