Database administrator

Duties

The duties of a database administrator vary and depend on the job description, corporate and Information Technology (IT) policies and the technical features and capabilities of the DBMS being administered. They nearly always include disaster recovery (backups and testing of backups), performance analysis and tuning, and some database design.

Definition of Database

A database is a collection of related information, accessed and managed by its DBMS. After experimenting with hierarchical and networked DBMSs during the 1970’s, the IT industry became dominated by relational DBMSs (Or Object Relational Database Management System) such as Oracle, Sybase, and, later on, Microsoft SQL Server and the like.

In a strictly technical sense, for any database to be defined as a "Truly Relational Model Database Management System," it should, ideally, adhere to the twelve rules defined by Edgar F. Codd, pioneer in the field of relational databases. To date, while many come close, it is admitted that nothing on the market adheres 100% to those rules, any more than they are 100% ANSI-SQL compliant.

While IBM and Oracle technically were the earliest on the RDBMS scene, many others have followed, and while it is unlikely that miniSQL still exist in their original form, Monty's MySQL is still extant and thriving, along with the Ingres-descended PostgreSQL. Alpha Five, Microsoft Access - the 1995+ versions, not the prior versions - were, despite various limitations, technically the closest thing to being 'Truly Relational' DBMS's for the desktop PC, with Visual FoxPro, and many other desktop products marketed at that time far less compliant with Codd's Rules.

A relational DBMS manages information about types of real-world things (entities) in the form of tables that represent the entities. A table is like a spreadsheet; each row represents a particular entity (instance), and each column represents a type of information about the entity (domain). Sometimes entities are made up of smaller related entities, such as orders and order lines; and so one of the challenges of a multi-user DBMS is provide data about related entities from the standpoint of an instant of logical consistency.

Properly managed relational databases minimize the need for application programs to contain information about the physical storage of the data they access. To maximize the isolation of programs from data structures, relational DBMSs restrict data access to the messaging protocol SQL, a nonprocedural language that limits the programmer to specifying desired results. This message-based interface was a building block for the decentralization of computer hardware, because a program and data structure with such a minimal point of contact become feasible to reside on separate computers.

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