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A data model organizes data elements and standardizes how the data elements relate to one another. Since data elements document real life people, places and things and the events between them, the data model represents reality, for example a house has many windows or a cat has two eyes. Computers are used for the accounting of these real life things and events and therefore the data model is a necessary standard to ensure exact communication between human beings. Data models are often used as an aid to communication between the business people defining the requirements for a computer system and the technical people defining the design in response to those requirements. They are used to show the data needed and created by business processes. Precise accounting and communication is a large expense and organizations traditionally paid the cost by having employees translate between themselves on an ad hoc basis. In critical situations such as air travel, healthcare and finance, it is becoming commonplace that the accounting and communication must be precise and therefore requires the use of common data models to obviate risk. According to Hoberman (2009), "A data model is a wayfinding tool for both business and IT professionals, which uses a set of symbols and text to precisely explain a subset of real information to improve communication within the organization and thereby lead to a more flexible and stable application environment."〔("Data Modeling Made Simple 2nd Edition", Steve Hoberman, Technics Publications, LLC 2009 )〕 A data model explicitly determines the structure of data. Data models are specified in a data modeling notation, which is often graphical in form.〔Michael R. McCaleb (1999). ("A Conceptual Data Model of Datum Systems" ). National Institute of Standards and Technology. August 1999.〕 A data model can be sometimes referred to as a data structure, especially in the context of programming languages. Data models are often complemented by function models, especially in the context of enterprise models. == Overview == Managing large quantities of structured and unstructured data is a primary function of information systems. Data models describe the structure, manipulation and integrity aspects of the data stored in data management systems such as relational databases. They typically do not describe unstructured data, such as word processing documents, email messages, pictures, digital audio, and video. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Data model」の詳細全文を読む スポンサード リンク
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