A very short overview is given of the principles of databases. The entity relationship model is used to define the conceptual base. Furthermore file management, the hierarchical model, the network model, the relational model and the object oriented model are discussed During the second world war, computers were used for encoding and decoding messages of the English and German army. Only after the war the computers were used for more reasonable and economical reasons. In the beginning of the fifties problems with typically a small amount of input data but for which complex calculations have to be made, were solved using computers. This was due to the small amount of memory and the long access time that was needed. Typical programming languages for this kind of problems emerged: Fortran, Algol and later on Pascal, C and C++. These languages however, were not user friendly enough, nor were they designed to handle huge amounts of complex data. So in the fifties we switched from simple file management to the use of a data structure that was more complex, but that enabled us to solve problems and answer questions that needed a huge quantity of data. We will first introduce the concept of a database and then we will look to a number of
different kinds of databases that have been used from 1960 until now.
|Title of host publication||Advances in Database Systems : Implementations and Applications|
|Editors||J. Paredaens, L. A. Tenenbaum|
|Place of Publication||Wien|
|Publication status||Published - 1994|
|Name||CISM Courses and Lectures|