Data are raw facts that constitute building blocks of information. Database is a collection of information and a means to manipulate data in a useful way, which must provide proper storage for large amounts of data, easy and fast access and facilitate the processing of data. Database Management System (DBMS) is a set of software that is used to define, store, manipulate and control the data in a database. From pre-stage flat-file system, to relational and object-relational systems, database technology has gone through several generations and its 40 years history.
- 1968 File-Based: predecessor of database, Data maintained in a flat file. Processing characteristics determined by common use of magnetic tape medium.
- 1968-1980 Era of non-relational database: A database provides integrated and structured collection of stored operational data which can be used or shared by application systems. Prominent hierarchical database model was IBM’s first DBMS called IMS. Prominent network database model was CODASYL DBTG model; IDMS was the most popular network DBMS.
- 1970-present Era of relational database and Database Management System (DBMS): Based on relational calculus, shared collection of logically related data and a description of this data, designed to meet the information needs of an organization; System catalog/metadata provides description of data to enable program-data independence; logically related data comprises entities, attributes, and relationships of an organization’s information. Data abstraction allows view level, a way of presenting data to a group of users and logical level, how data is understood to be when writing queries.
Example Database Systems are:
- Microsoft Corp- SQL Server
- Oracle- Oracle 9i
- IBM – IMS/DB, DB2
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