Database

See also: Base, data base, BDD, dB

A database , usually shortened in data base or BDD , is a structured and organized unit allowing the storage of great quantities of information in order to facilitate the exploitation of it (addition, update, data retrieval).

A database results physically in a whole of files present on a Mass memory (very often a disc). Some can be accessible via the network X, one speaks then basic about data on line.

There exist several types of bases:

Structure

The most important point to be able to consider a software as a database is its process with the competitor access to the data/recordings. This point is paramount to allow the sustainable development, sedentary, distributed and effective of a database.

Hierarchical databases

See also the hierarchical article Database .

The first data-processing system was conceived for the management of the data of the Programme Apollo of NASA. The data were structured in Hiérarchie S, comparable with the organization of the repertories on a PC. But certain problems of storage carried out to use (and thus to invent) databases of the networks type. The files XML are a modern reminiscence of the hierarchical bases and there thus exist native databases XML.

Databases networks

See also the article Database network .

Network model has a structure in the form of graph where the entities are connected between them using logical pointers. This basic model of data was invented by Charles.W. Bachman. For its model, it accepted in 1973 the Prix Turing.

Relational databases

See also the article relational Database .

In 1970, at the time when the systems resting on the hierarchical model or the model in network were under development full, Edgar Frank Codd published an article where he proposed to store heterogeneous data in tables , allowing to establish relations between them. Nowadays, this model is extremely widespread, but in 1970, this idea was regarded as an intellectual curiosity. It was doubted whereas the tables can be ever managed efficiently by a computer. This skepticism however did not prevent E.F. Codd to continue its research.
Un first prototype of Management system of relational databases (SGBDR) is built in the laboratories of IBM. Since the Years 1980, this technology matured and was adopted by industry. In 1987, the language SQL, an extension of the relational Algebra, is standardized. At present, the SGBDR are present in many software, are very widespread in the databases and represent an industry of several billion dollars.

Directed databases object

See also the article directed Database object .

The most known examples at present basic of directed data objects are the Annuaire S, which are able to store a multitude of information. They store it in Objet S , very often an individual record sheet, a machine, a resource… with which one associates values, its attributes.

Semi-structured databases

Multidimensional databases

They make it possible to store various numerical data with the crossings of the " n" axes corresponding to the " n" dimensions of the base.

It is then possible to sail in this space, at various levels of aggregates (zooms, rotation of axes, etc): these databases are called cubic or hypercubes in decisional Informatique and are often used in the trades of the control of management and control.

Native databases XML

See also the article native Base XML .

These databases are based on the structure offered by the language XML to store the Donnée S and to locate them.

They represent a big change of the basic concept of data making it possible to store large volumes of Donnée S or Document S, including Multimédia.

The organization of the data in language XML remains however Hiérarchique.

Schematization of this structure: the conceptual diagram

See also the article conceptual Diagram .

Contents and use

Bibliographical databases

Their structure is reduced to a collection of bibliographic records, but of which the recordings can be structures having of many parameters of variability.

See also: Database bibliographical

Chemical databases

See also: Database chemical

Decisional databases

See also: Data-processing decisional

The decisional databases are used in intensive reading, within the framework of the decision-making aid. Their contents come from the whole of the databases of production (RH, inventory control, commercial management, production control, Marketing, etc) by scripts and batchs, or by tools of the type LTE, EAI or ESB.

The Datawarehouse and Datamart are examples of relational bases used in a decisional way.

The multidimensional databases (cubic multidimensional) are generally used in a decisional way.

Factual databases

Database gathering of the data established and attested concerning a particular field. A database factual can integrate nontextual data like graphs, diagrams… In this case, certain authors prefer speech of " bank of données".

Geographical databases (SIG)

See also: geographical Information system

Databases multi-media

See also: multi-media Database

See too

Related article

External bonds

  • Applications of the Databases in Social sciences
  • Introduction to the Design of the Relational Databases
  • Introduction to the Databases Multivalué
  • database the segmentation of the households according to the habitat, the family, the environment, the inheritance
  • database on the behavior of purchase of the households

  • Political of management of the rights of access to a database

Be-X-old: Базададзеных Simple: Database

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