DBA 5/20/2018 Like a policeman or teacher Unstated responsibilities, expectations Most people don’t know what a DBA does.

DBA Centralized control of the database is exerted by a person or group of persons under the supervision of a high level administrator. This person or group is referred to as the database administrator (DBA). They are the users who are most familiar with the database and are responsible for creating, modifying, and maintaining its three levels. Database Administrator is responsible to manage the DBMS’s use and ensure that the database is functioning properly.

Definition DBA administers the three levels of database and consultation with the overall user community, sets up the definition of the global view of the various users and applications. He is responsible the definition and implementation of the internal level, including the storage structure and access methods to be used for the optimum performance of the DBMS. DBA is responsible for granting permission to the users of the database and stores the profile of each user in the database

Database administration is more of an operational or technical level function responsible for physical database design, security enforcement, and database performance.  Tasks include maintaining the data dictionary, monitoring performance, and enforcing organizational standards and security. 

Responsibilities of DBA 1. Deciding the information content of the database It is the DBA’s job to decide exactly what information is to be held in the database - in other words, to identify the entities of interest to the enterprise To identify the information to be recorded about those entities. The DBA must then define the content of the database by writing the conceptual schema.

2. Deciding the storage structure and access strategy The DBA must also decide how the data is to be represented in the database, and must specify the representation by writing the storage structure definition. In addition, the associated mapping between storage structure definition and the conceptual schema must also be specified.

3. Liaising with the users It is the business of the DBA to liaise with users, to ensure that the data they require is available, and to write the necessary external schemas. In addition, the mapping between any given external schema and the conceptual schema must also be specified. In practice the external DDL will probably include the means for specifying the mapping, but the schema and the mapping should be clearly distinguishable.

4. Defining authorization checks and validation procedures Authorization checks and validation procedures may be considered as logical extensions of the conceptual schema. The conceptual DDL will include facilities for specifying such checks and procedures. Security Access restrictions ensure that the database is secure. Passwords, encryption, and views implement security. Effective password protection is critical.

5. Defining a strategy for backup and recovery Once an enterprise is committed to a database, it become critically dependent on the successful operation of that system. In the event of damage to any portion of the database – caused by human error, say, or a failure in the hardware or supporting operating system – it is essential to be able to repair the data concerned with a minimum of delay and with as little effect as possible on the rest of the system.

6. Monitoring performance and responsibilities to changes in requirements The DBA is responsible for so organizing the system as to get the performance that is “best for the enterprise” and for making the appropriate adjustments change. Any change to details of storage and access must be accompanied by a corresponding change to the definition of the mapping to storage, so that the conceptual schema may remain constant

Disaster Recovery

Archives An archive is a place where corporate data is kept. Information in an archive is removed from the database and stored in the archive for future reference. Archives are usually kept in a mass-storage device like a disk, tape, CD, or a DVD. It is important such archives be kept off-site to allow recovery should disaster strike

Planning for Disaster Databases can be harmed from hardware and software malfunctions, and outsides forces like floods and power outages. DBA’s must take active role in formulating disaster recovery plans.

Data Dictionary Management Essentially the catalog, but it contains a wider range of information, including information on tables, fields, indexes, and programs. The DBA manages and updates the data dictionary, which establishes naming conventions for tables, fields, etc., and data integrity rules.

Additional responsibilities of DBA Training DBA gives training on the DBMS and how to access the database DBMS Support The DBA is charged with all aspects of a DBMS, including selection and management DBA must evaluate each prospective DBMS using a checklist like that shown in figure. Database design DBA is responsible for tuning the design, i.e., making changes that improve system performance.

DBA time breakdown 22% Fire Fighting 33% Monitoring 12% Perf. Tuning / Change Mgt. 33% Development Support 0% Planning for growth 0% Backup & Recovery Planning 0% Learning Koopman

Types of DBAs: Development DBA May carry developer title Develop code ( PL/SQL ) “Hunter” personality (find/fix/forget) Best practices: Code Complete by McConnell

Production Support DBA Keep it running “shepherd / farmer” personality Where best practices really make a difference The hero isn’t the DBA that battles problems through the weekend, but the one that avoided the problem

Application DBA Supports a business critical app. like Oracle Financials, SAP, Peoplesoft, Lawson Production support, some dev. Key skill: understands how the app. Interacts with Oracle