ERモデル
別名:実体関連モデル
【英】Entity-Relationship Model, ER Model, ERM
ERモデルとは、ある世界を「エンティティ」(実体)、「アトリビュート」(属性)、「リレーションシップ」(関連)という3つの構成要素を用いて概念化したデータモデルのことである。
ERモデルにおいて、エンティティは、管理の対象を指し、アトリビュートは、それぞれの実体に備わる特性や付随的な要素を指す。リレーションシップは、実体と実体との相互関係を表す。
ERモデルを表記する手法として、ERダイアグラム(ERD)と呼ばれる表記法が併せて考案されている。ERDでは、実体を長方形で、属性をひし形で、関係を矢印で表現する。
ERモデルは1970年代にピーター・チェン(Peter Chen)によって提唱された。主にリレーショナルデータベース(RDB)の設計などにおいてERモデルは多用されている。
実体関連モデル
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出典: フリー百科事典『ウィキペディア(Wikipedia)』 (2023/02/02 13:42 UTC 版)
- ^ a b "The Entity Relationship Model: Toward a Unified View of Data" for entity–relationship modeling.
- ^ A.P.G. Brown, "Modelling a Real-World System and Designing a Schema to Represent It", in Douque and Nijssen (eds.), Data Base Description, North-Holland, 1975, ISBN 0-7204-2833-5.
- ^ 英: entity
- ^ 英: relationship
- ^ Paul Beynon-Davies (2004). Database Systems. Houndmills, Basingstoke, UK: Palgrave
- ^ ERROL
- ^ RRA: A Reshaped Relational Algebra
- ^ "English, Chinese and ER diagrams" by Peter Chen.
- ^ Hubert Tardieu, Arnold Rochfeld and René Colletti La methode MERISE: Principes et outils (Paperback - 1983)
- ^ Elmasri, Ramez, B. Shamkant, Navathe, Fundamentals of Database Systems, third ed., Addison-Wesley, Menlo Park, CA, USA, 2000.
- ^ ER 2004 : 23rd International Conference on Conceptual Modeling, Shanghai, China, November 8-12, 2004
- ^ A Formal Treatment of UML Class Diagrams as an Efficient Method for Configuration Management 2007
- ^ James Dullea, Il-Yeol Song, Ioanna Lamprou - An analysis of structural validity in entity-relationship modeling 2002
- ^ Hartmann, Sven. "Reasoning about participation constraints and Chen's constraints". Proceedings of the 14th Australasian database conference-Volume 17. Australian Computer Society, Inc., 2003.
- ^ IDEF1X(2007年6月22日時点のアーカイブ)
- ^ Kent in "Data and Reality" : "One thing we ought to have clear in our minds at the outset of a modelling endeavour is whether we are intent on describing a portion of "reality" (some human enterprise) or a data processing activity."
- ^ Abrial in "Data Semantics" : "... the so called "logical" definition and manipulation of data are still influenced (sometimes unconsciously) by the "physical" storage and retrieval mechanisms currently available on computer systems."
- ^ Stamper: "They pretend to describe entity types, but the vocabulary is from data processing: fields, data items, values. Naming rules don't reflect the conventions we use for naming people and things; they reflect instead techniques for locating records in files."
- ^ In Jackson's words: "The developer begins by creating a model of the reality with which the system is concerned, the reality which furnishes its [the system's] subject matter ..."
- ^ Elmasri, Navathe: "The ER model concepts are designed to be closer to the user’s perception of data and are not meant to describe the way in which data will be stored in the computer."
- ^ "UML as a Data Modeling Notation, Part 2"
- ^ P. Chen. Suggested research directions for a new frontier: Active conceptual modeling. ER 2006, volume 4215 of Lecture Notes in Computer Science, pages 1–4. Springer Berlin / Heidelberg, 2006.
- ^ M. L. Brodie and J. T. Liu. The power and limits of relational technology in the age of information ecosystems. On The Move Federated Conferences, 2010.
- ^ A. Badia and D. Lemire. A call to arms: revisiting database design. SIGMOD Record 40, 3 (November 2011), 61-69.
- ^ Gregersen, Heidi, and Christian S. Jensen. "Temporal Entity-Relationship models—a survey." IEEE Transactions on Knowledge and Data Engineering, 11.3 (1999): 464-497.
- ^ RICCARDO TORLONE (2003). “Conceptual Multidimensional Models”. In Maurizio Rafanelli. Multidimensional Databases: Problems and Solutions. Idea Group Inc (IGI). ISBN 978-1-59140-053-0
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