A collection of data, arranged for uniform search and retrieval.
The actual form can vary wildly. FlatFiles and CSVs are very simple databases. HierarchicalDataBases are one of the longest-established types of DataBase, with GDBM being a prime example. XMLDataBases are currently flavour of the month for all sorts of reasons. But the most widely used form are RelationalDataBases and their practical offspring PostRelationalDataBases.
InformationSystems such as MG use InvertedIndexes, which serve to both compress and index natural language text.
38 pages link to DataBase:
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