(Continued from previous part...)

DBA Tasks, Responsibilities and Skills Required

DBA Responsibilities:

The job of the DBA seems to be everything that everyone else either doesn't want to do, or doesn't have the ability to do. DBAs get the enviable task of figuring out all of the things no one else can figure out. More seriously though, here is a list of typical DBA responsibilities:
. Installation, configuration and upgrading of Oracle server software and related products
. Evaluate Oracle features and Oracle related products
. Establish and maintain sound backup and recovery policies and procedures
. Take care of the Database design and implementation
. Implement and maintain database security (create and maintain users and roles, assign privileges)
. Perform database tuning and performance monitoring
. Perform application tuning and performance monitoring
. Setup and maintain documentation and standards
. Plan growth and changes (capacity planning)
. Work as part of a team and provide 7x24 support when required
. Perform general technical trouble shooting and give consultation to development teams
. Interface with Oracle Corporation for technical support.

Required Skills:

. Good understanding of the Oracle database, related utilities and tools
. A good understanding of the underlying operating system
. A good knowledge of the physical database design
. Ability to perform both Oracle and operating system performance tuning and monitoring
. Knowledge of ALL Oracle backup and recovery scenarios
. A good knowledge of Oracle security management
. A good knowledge of how Oracle acquires and manages resources
. A good knowledge Oracle data integrity
. Sound knowledge of the implemented application systems
. Experience in code migration, database change management and data management through the
various stages of the development life cycle
. A sound knowledge of both database and system performance tuning
. A DBA should have sound communication skills with management, development teams, vendors
and systems administrators
. Provide a strategic database direction for the organisation
. A DBA should have the ability to handle multiple projects and deadlines
. A DBA should possess a sound understanding of the business

Interview Questions

• Tell us about yourself/ your background.
  
• What are the three major characteristics that you bring to the job market?
  
• What motivates you to do a good job?
  
• What two or three things are most important to you at work?
  
• What qualities do you think are essential to be successful in this kind of work?
  
• What courses did you attend? What job certifications do you hold?
  
• What subjects/courses did you excel in? Why?
  
• What subjects/courses gave you trouble? Why?
  
• How does your previous work experience prepare you for this position?
  
• How do you define 'success'?
  
• What has been your most significant accomplishment to date?
  
• Describe a challenge you encountered and how you dealt with it.
• Describe a failure and how you dealt with it.
• Describe the 'ideal' job... the 'ideal' supervisor.
• What leadership roles have you held?
• What prejudices do you hold?
• What do you like to do in your spare time?
• What are your career goals (a) 3 years from now; (b) 10 years from now?
• How does this position match your career goals?
• What have you done in the past year to improve yourself?
• In what areas do you feel you need further education and training to be successful?
• What do you know about our company?
• Why do you want to work for this company. Why should we hire you?
• Where do you see yourself fitting in to this organization . . .initially? . . .in 5 years?
• Why are you looking for a new job?
• Are you willing to travel?
• What are your salary requirements?
• When would you be available to start if you were selected?
• Did you use online or off-line backups?
• What version of Oracle were you running?
• Haw many databases and what sizes?
• If you have to advise a backup strategy for a new application, how would you approach it and what questions will you ask?
• If a customer calls you about a hanging database session, what will you do to resolve it?
• Compare Oracle to any other database that you know. Why would you prefer to work on one and not on the other?

Rules for Relational Databases

THE RULES:

0. (Yes, there is a Rule 0!)
For a system to qualify as a RELATIONAL, DATABASE, MANAGEMENT system, that system must use its RELATIONAL facilities (exclusively) to MANAGE the DATABASE.

1. The information rule
The information rule simply requires all information in the database to be represented in one and only one way, Namely by values in column positions within rows of tables.

2. The guaranteed access rule
This rule is essentially a restatement of the fundamental requirement for primary keys. It says that every individual scalar value in the database must be logically addressable by specifying the mane of the containing table, the name of the containing column and the
Primary key value of the containing row.

3. Systematic treatment of null values
The DBMS is required to support a representation of "missing information and inapplicable Information" that is systematic, distinct from all regular values (for example, "distinct from zero or any other number," in the case of numeric values), and independent of data type. It is also implied that such representations must be manipulated by the DBMS in a systematic way.
4. Active online catalog based on the relational model
The system is required to support an online, inline, relational catalog that is accessible to authorized users by means of their regular query language.

5. The comprehensive data sub language rule The system must support a least one relational language that
(a) Has a linear syntax,
(b) Can be used both interactively and within application programs, and © supports data definition operations (including view definitions), data manipulation operations (update as well as retrieval), security and integrity constraints, and transaction management operations (begin, commit, and rollback).

6. The view-updating rule
All views that are theoretically up datable must be updatable by the system.

7. High-level insert, update, and delete
The system must support set-at-a-time INSERT, UPDATE, and DELETE operators.
8. Physical data independence
Self-explanatory.

9. Logical data independence
Self-explanatory

10. Integrity independence
Integrity constraints must be specified separately from application programs and stored in the catalog. It must be possible to change such constraints as and when appropriate without unnecessarily affecting existing applications.

11. Distribution independence Existing applications should continue to operate successfully
(a) When a distributed version of the DBMS is first introduced;
(b) When existing distributed data is redistributed around the system.

12. The nonsubversion rule
If the system provides a low-level (record-at-a-time) interface, then that interface cannot be used to subvert the system (e.g.) bypassing a relational security or integrity constraint.