Database administration

 Create database (create tablespace)
 Creating User
 Managing Users
 Granting privileges
 Managing password
 Removing privileges

DATABASE
 Collection of coherent data
 To create database we have :
Syntax: CREATE DATABASE <database_name>
Eg: CREATE DATABASE my_db;

TABLESPACE
The oracle database consist of one or more logical storage units
called tablespaces.
Each tablespace in an Oracle database consists of one or more
files called datafiles, which are physical structures that confirm
to the operating system in which Oracle is running.
Syntax:
CREATE<tablespace name> DATAFILE
'C:oraclexeapporacleproduct10.2.0server<file name.dbf ’
SIZE 50M;
Eg:
Create table space SY_MCA DATAFILE
‘'C:oraclexeapporacleproduct10.2.0serverusr.dbf' ’SIZE 50M;

Create User
The DBA creates user by executing CREATE USER statement.
The user is someone who connects to the database if enough
privilege is granted.
Syntax:
SQL> CREATE USER < username> -- (name of user to be created )
IDENTIFIED BY <password> -- (specifies that the user must
login with this password)
SQL> user created
Eg: create user James identified by bob;
(The user does not have privilege at this time, it has to be granted.
These privileges determine what user can do at database level.)

Privileges
A privilege is a right to execute an SQL statement or to access
another user's object.
In Oracle, there are two types of privileges
 System Privileges
 Object Privileges
 System Privileges : are those through which the user can
manage the performance of database actions. It is normally
granted by DBA to users.
Eg: Create Session,Create Table,Create user etc..
 Object Privileges : allow access to objects or privileges on
object, i.e. tables, table columns. tables,views etc..It includes
alter,delete,insert,select update etc.
(After creating the user, DBA grant specific system privileges to user)

GRANT :
The DBA uses the GRANT statement to allocate system
privileges to other user.
Syntax:
SQL> GRANT privilege [privilege…. … ]
TO USER ;
SQL> Grant succeeded
Eg: Grant create session, create table, create view to James;

Object privileges vary from object to object. An owner has all
privilege or specific privileges on object.
SQL> GRANT object_priv [(column)]
ON object
TO user;
SQL>GRANT select, insert ON emp TO James;
SQL>GRANT select ,update (e_name,e_address)
ON emp TO James;

CHANGE PASSWORD
The DBA creates an account and initializes a password for every
user.You can change password by using ALTER USER
statement.
Syntax:
Alter USER <some user name>
IDENTIFIED BY<New password>
Eg: ALTER USER James
IDENTIFIED BY sam

ROLE:
A role is a named group of related privileges that can be granted
to user.In other words, role is a predefined collection of
previleges that are grouped together,thus privileges are easier
to assign user.
SQL> Create role custom;
SQL> Grant create table, create view TO custom;
SQL> Grant select, insert ON emp TO custom;
Eg: Grant custom to James, Steve;

REVOKE
REVOKE statement is used to remove privileges granted to other
users. The privileges you specify are revoked from the users.
Syntax:
REVOKE [privilege.. …]
ON object
FROM user
Eg:
 REVOKE create session,create table from James;
 REVOKE select ,insert
ON emp
FROM James

Database administration

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