A database is a collection of information that is organized in such a way that a computer program can choose a desired piece of information required. In a database, the information can be easily updated, managed or accessed. Often abbreviated as DB, we can think of a database as an electronic filing system. We can also think of database as the collection of schema, queries, views, tables, reports, and other objects.
Traditional databases are organized by files, records, and fields. A field is a single piece of information, a record is set of fields and a file is a collection of records. For example, a telephone book is comparable to a file. It contains a list of records, each of which consists of different fields such as name, address, telephone number etc.
Relational databases are tabular databases in which data can be accessed or reorganized in a number of different ways. In this model, data is organized into tables of rows and columns, with a unique key identifying each row. The rows represent instances of the entity and the columns represent values attributed to that instance.
A distributed database is one that can be dispersed or replicated among different points in a network or it may be stored in multiple computers, located in the same physical location. The collection of data can be distributed across multiple physical locations by system administrators. Because they store data across multiple computers, distributed databases may improve performance at end-user work-sites.
An object-oriented database is one that is congruent with the data defined in object classes and sub-classes. Object-oriented database management systems(OODBMS) allow object-oriented programmers to develop, modify or replicate the objects to make new objects within OODBMS. Some object-oriented databases are designed to work well with object-oriented programming languages such as Delphi, Ruby, Python, Perl, Java, C#, Visual Basic .NET, C++.
To access information from a database, you need a database management system commonly abbreviated as DBMS. DBMS is computer software application that interacts with the user, other applications and the database itself to analyze data. This is a collection of programs that enables you to enter, organize, and select data in a database. There are many different types of DBMS, ranging from small systems that run on personal computers to huge systems that run on mainframes. Well-known DBMSs include MySQL, MongoDB, Microsoft SQL Server, Oracle, IBM DB2.
Computer databases typically contain aggregations of data records or files. Database administrator manages those records and provides users the capabilities of controlling read/write access, specifying report generation, and analyzing the database usage. The role of database administrator in maintaining the database include capacity planning, installation, configuration, database designing, migration, performance monitoring, security, troubleshooting, as well as backup and data recovery. Some other responsibilities of database administrator are ensuring compliance with database vendor license agreement, modifying the database structure as necessary from information given by developers, maintaining archived data, generating various reports by querying from the database as per need and contacting database vendor for technical support.