A national database (NDB) or an international one (abbreviated IDB), also named often as “data bankâ€, represents a method of storing some information and data on an external device (a storage device), with the possibility of an easy extension or an easy way to quickly find these information. Therefore, through IDB we don`t only understand a bibliometric or bibliographic index, which is a collection of references, that normally represents the “softâ€, but also the respective IDB “hardâ€, which is the support and the storage technology. Usually, a database – a very comprehensive notion in the computer’s science – is a bibliographic index, compiled with specific purpose, objectives and means. In reality, the national and international databases are operated through management systems, usually electronic and informational, based on advanced manipulation technologies in the virtual space. On line encyclopedias can also be considered and are important international database (IDB). WorldCat, for example, is a world catalogue, that included the identification data for the books within circa 71.000 libraries in 112 countries, data classified through Online Computer Library Center (OCLC), with the participation of the libraries in the respective countries, especially of those that are national library.
