MYSQL COMMANDS

1. Opening and logging into mysql Server

$ mysql -u root -p

password:root

2. To see all the Databases in the mysql Server

mysql> show databases;

DDL

Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples: Create, Alter, Truncate, Drop and Rename.

3. CREATE

To create a New Database in the mysql Server

mysql> create database databasename;

4. To use the particular Database;

mysql> use databasename;

5. To create a Table (say department) in the Database

mysql> create table department(id int, name varchar(255));

6. ALTER

Alter the table (say department) by adding the new column.

ALTER TABLE table_name

ADD column_name datatype;

eg;

mysql> alter table department add age int;

7. TRUNCATE

Truncate removes all rows from a table. Truncate the table (say department) by using following command

mysql> truncate table department;

8. DROP

The DROP command removes a table from the database. Drop the table (say department) by following command.

mysql> drop table department;

9. RENAME

It renames the table in database. Rename (say department into employee) by using following command.

mysql> rename table department to employee;

DML

Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples: insert, select, delete and updates.

10. INSERT

>Insert data into a table. To add a row in the Table (say in the department table)

mysql> insert into department(id,name)values(1,"admin");

>To add multiple rows in the Table (say in the department table)

insert into department(id,name)values(2,"staffroom"),(3,"classroom"),(4,"Lab");

11. SELECT

Retrieves data from the a database. To see the row/tuple is added in Table (say department table)

mysql> select * from department;

>To see the complete description of a particular table;

describe table_name;

eg:

mysql> describe department;

>To see the list of Tables in the Database

mysql> show tables;

> To count the number of rows in the table (say department)

mysql> select count(*) from department;

12. DELETE

>To delete a row from Table. (say department table)

mysql> delete from department where id=3;

>To see whether the row is deleted from the Table.

mysql> select * from department;

13. UPDATE

Updates the existing data within a table.

UPDATE table_name

SET column1=value1,column2=value2,...

WHERE some_column=some_value;

> To update department name from computers to civil of one tuple which had id=2;

mysql> update department set name=civil where id=2;

DCL

Data Control Language (DCL) statements. Some examples:

GRANT - gives user's access privileges to database

REVOKE - withdraw access privileges given with the GRANT command

To Create a new user

CREATE USER 'jeffrey'@'localhost';

14. GRANT

GRANT privilege_name

ON object_name

TO {user_name |PUBLIC |role_name}

[WITH GRANT OPTION];

privilege_name is the access right or privilege granted to the user. Some of the access rights are ALL, EXECUTE, and SELECT.

object_name is the name of an database object like TABLE, VIEW, STORED PROC and SEQUENCE.

user_name is the name of the user to whom an access right is being granted.

PUBLIC is used to grant access rights to all users.

ROLES are a set of privileges grouped together.

WITH GRANT OPTION - allows a user to grant access rights to other users.

Privileges and Roles:

Privileges: Privileges defines the access rights provided to a user on a database object. There are two types of privileges.

1) System privileges - This allows the user to CREATE, ALTER, or DROP database objects.

2) Object privileges - This allows the user to EXECUTE, SELECT, INSERT, UPDATE, or DELETE data from database objects to which the privileges apply.

Few CREATE system privileges are listed below:

System Privileges	Description
CREATE	Allows users to create the specified object in their own schema.
CREATE ANY	Allows users to create the specified object in any schema.

The above rules also apply for ALTER and DROP system privileges.

Few of the object privileges are listed below:

Object Privileges	Description
INSERT	allows users to insert rows into a table.
SELECT	allows users to select data from a database object.
UPDATE	allows user to update data in a table.
EXECUTE	allows user to execute a stored procedure or a function.

> In beginnng user is “root”. Create a new user say “aiktc” using the following command.

mysql> create user 'aiktc'@'localhost';

> From the “root” give grant permission to the new “aiktc” user for the particular database (say college)

GRANT all

ON college

TO aiktc;

> Log in as aiktc and type show databases command and college database will be listed there. “All” permission is given by the root user so all the database activity (DML and DDL) can be performed on the database.

15. REVOKE

REVOKE privilege_name

ON object_name

FROM {user_name |PUBLIC |role_name}

> If “root” user wants to remove or revoke the permission given to the “aiktc” user, the following command can be used.

REVOKE all

ON college

TO aiktc;