How To Protect Your database

The clauses of the CREATE DATABASE statement used for specifying the passwords for users SYS and SYSTEM are:

- USER SYS IDENTIFIED BY password
- USER SYSTEM IDENTIFIED BY password
If not specified, these users are assigned the default passwords change_on_install and manager, respectively. A record is written to the alert file indicating that the default passwords were used. To protect your database, you should change these passwords using the ALTER USER statement after database creation.

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Protecting Your Database

The clauses of the CREATE DATABASE statement used for specifying the passwords for users SYS and SYSTEM are:

• ·       USER SYS IDENTIFIED BY password
•       USER SYSTEM IDENTIFIED BY password

If you omit these clauses, these users are assigned the default passwords change_on_install and manager, respectively. A record is written to the alert log indicating that the default passwords were used. To protect your database, you must change these passwords using the ALTER USER statement immediately after database creation.

Oracle strongly recommends that you specify these clauses, even though they are optional in this release of Oracle Database. The default passwords are commonly known, and if you neglect to change them later, you leave database vulnerable to attack by malicious users.

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Administrative Privileges

Administrative privileges that are required for an administrator to perform basic database operations are granted through two special system privileges, SYSDBA and SYSOPER. You must have one of these privileges granted to you, depending upon the level of authorization you require.

The SYSDBA and SYSOPER system privileges allow access to a database instance even when the database is not open. Control of these privileges is totally outside of the database itself.

The SYSDBA and SYSOPER privileges can also be thought of as types of connections that enable you to perform certain database operations for which privileges cannot be granted in any other fashion. For example, you if you have the SYSDBA privilege, you can connect to the database by specifying CONNECT AS SYSDBA.

SYSDBA and SYSOPER

SYSDBA               

• Perform STARTUP and SHUTDOWN operations
• ALTER DATABASE: open, mount, back up, or change character set
• CREATE DATABASE
• DROP DATABASE
• CREATE SPFILE
• ALTER DATABASE ARCHIVELOG
• ALTER DATABASE RECOVER
• Includes the RESTRICTED SESSION privilege

SYSOPER             

• Perform STARTUP and SHUTDOWN operations
• CREATE SPFILE
• ALTER DATABASE OPEN/MOUNT/BACKUP
• ALTER DATABASE ARCHIVELOGALTER DATABASE RECOVER (Complete recovery only. Any form of incomplete recovery, such as UNTIL TIME|CHANGE|CANCEL|CONTROLFILE requires connecting as SYSDBA.)
• Includes the RESTRICTED SESSION privilege

Related Post:-

• Authentication Method for Database Administrators

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Database Administrator Security and Privileges

To perform the administrative tasks of an Oracle Database DBA, you need specific privileges within the database and possibly in the operating system of the server on which the database runs. Access to a database administrator's account should be tightly controlled.

This section contains the following topics:

• ·         The Database Administrator's Operating System Account
•        Administrative User Accounts

 The Database Administrator's Operating System Account

To perform many of the administrative duties for a database, you must be able to execute operating system commands. Depending on the operating system on which Oracle Database is running, you might need an operating system account or ID to gain access to the operating system. If so, your operating system account might require operating system privileges or access rights that other database users do not require (for example, to perform Oracle Database software installation). Although you do not need the Oracle Database files to be stored in your account, you should have access to them.

Administrative User Accounts

Two administrative user accounts are automatically created when Oracle Database is installed:

• SYS (default password: CHANGE_ON_INSTALL)
• SYSTEM (default password: MANAGER)

 SYS

When you create an Oracle Database, the user SYS is automatically created and granted the DBA role. All of the base tables and views for the database data dictionary are stored in the schema SYS. These base tables and views are critical for the operation of Oracle Database. To maintain the integrity of the data dictionary, tables in the SYS schema are manipulated only by the database. They should never be modified by any user or database administrator, and no one should create any tables in the schema of user SYS. (However, you can change the storage parameters of the data dictionary settings if necessary.) Ensure that most database users are never able to connect to Oracle Database using the SYS account.

SYSTEM

When you create an Oracle Database, the user SYSTEM is also automatically created and granted the DBA role. The SYSTEM username is used to create additional tables and views that display administrative information, and internal tables and views used by various Oracle Database options and tools. Never use the SYSTEM schema to store tables of interest to non-administrative users.

Related Post :-

• Protecting Your Database
• DBA Role
• Administrative Privileges 

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Relational Database Management System (RDBMS)

RDBMS is a DBMS in which data is stored in tables and the relationships among the data are also stored in tables. The data can be accessed or reassembled in many different ways without having to change the table forms.

A relational database management system (RDBMS) is introduced by E.F Codd But Oracle provides a flexible RDBMS called Oracle9i. Using its features, you can store and manage data with all the advantages of a relational structure plus PL/SQL, an engine that provides you with the ability to store and execute program units. Oracle9i also supports Java and XML. The Oracle server offers the options of retrieving data based on optimization techniques. It includes security features that control how a database is accessed and used. Other features include consistency and protection of data through locking mechanisms.

The Oracle9i server provides an open, comprehensive, and integrated approach to information management. An Oracle server consists of an Oracle database and an Oracle server instance. Every time a database is started, a system global area (SGA) is allocated, and Oracle background processes are started. The system global area is an area of memory used for database information shared by the database users. The combination of the background processes and memory buffers is called an Oracle instance.

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Oracle Database

Oracle introduced the first commercial Relational Database Management System (RDBMS) almost 30 years ago. Oracle database consists of operating system files, also known as database files, that provide the actual physical storage for database information. The database files are used to ensure that the data is kept consistent and can be recovered in the event of a failure of the instance.

The general purpose of a database is to store and retrieve related information. An Oracle database has a logical and a physical structure. The physical structure of the database is the set of operating system files in the database. An Oracle database consists of three file types.

• Data files containing the actual data in the database
• Redo logs containing a record of changes made to the database to enable recovery of     the data in case of failures
• Control files containing information necessary to maintain and verify database integrity Other Key File Structures

     The Oracle server also uses other files that are not part of the database:  

• The parameter file defines the characteristics of an Oracle instance. For example, it contains parameters that size some of the memory structures in the SGA.
• The password file authenticates users privileged to start up and shut down an Oracle instance.
• Archived redo log files are offline copies of the redo log files that may be necessary to recover from media failures.

Related video:- Introduction to Oracle Database Administration - Oracle DBA

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How to Become a Database Administrator

While searching jobs some people go for database administrator but not many people know how to become a database administrator. When we talk about a particular job, it is necessary to know what the job is about and its prospect in future. Before the implantation of computers and laptops in one word electronic gadgets, data of office, schools, industry, factory and other places were recorded in note books. This particular process was quite length and time consuming......

Even it was very difficult when one required to a particular data. The individual has to go through considerable amount of sheets in order to one data. Lots of places were also required to keep them in files. Moreover, the entire process was time consuming and quite boring also. For the particular work quite a number of persons were needed to be appointed.

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Database Adminstrator

In this new era of information technology, data and information is central and a key aspect of any company’s business activities. This data and information must be logged, backed-up, protected but most importantly easily available for staff to use to make crucial business decisions. As a result, there must be people in charge of managing this data and these people are called database administrators.

A database administrator (short form DBA) is a person responsible for the design, implementation, maintenance and repair of an organization's database. They are also known by the titles Database Coordinator or Database Programmer, and is closely related to the Database Analyst, Database Modeller, Programmer Analyst, and Systems Manager. The role includes the development and design of database strategies, monitoring and improving database performance and capacity, and planning for future expansion requirements. They may also plan, co-ordinate and implement security measures to safeguard the database.

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