A database (DB) can be understood as an organized collection of data that serves a central purpose. The organization of the data includes its storage, formatting, management, access, manipulation and presentation in a consistent form. The data stored in the database is structured in such a way that it is available to the executed processes in the shortest possible time.
A database is an electronic archive that is characterized by rapid access and space-saving storage of large amounts of data. Data or messages can be designed or retrieved according to a variable ordering scheme, either individually or linked, both for dialog operation and for batch processing (according to DIN 44300 for the management of the data or files contained). A database can be shared by several users and application programs. A distinction is made between the arrangement of the data, taking into account the optimal use of memory, and the logical data structure, which results from the relationship between related data. As a result, data is managed according to uniform criteria, regardless of the requirements of its particular application.
Structures of databases
In addition to text-based databases, there are those that can manage graphics, images, audio, video, and compound documents in addition to text and numerics. Depending on the structure and application of the database, a distinction is made between distributed databases, relational databases, public, graphic-oriented databases, object-oriented and object-relational databases.
Databases are queried using query languages, the best known of which for relational databases is the Structured Query Language( SQL). An implementation of SQL takes place in MySQL. In contrast to this are the databases that are not based on SQL, the Not Only SQL databases, NoSQL. Another database language is Multidimensional Expression( MDX), which is used as a search tool in multidimensionally prepared data sets.