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Anchor Modeling is an agile database modeling technique suited for information that changes over time both in structure and content. It provides a graphical notation used for conceptual modeling similar to that of entity—relationship modeling, with extensions for working with temporal data. The modeling technique involves four modeling constructs: the anchor, attribute, tie and knot, each capturing different aspects of the domain being modeled.〔 (Preprint available (here )) 〕 The resulting models can be translated to physical database designs using formalized rules. When such a translation is done the tables in the relational database will mostly be in the sixth normal form. ==Philosophy and history== Anchor Modeling was created in order to take advantage of the benefits from a high degree of normalization while avoiding its drawbacks. Advantages such as being able to non-destructively evolve the model, avoid null values, and keep the information free from redundancies are gained. Performance issues due to extra joins are largely avoided thanks to a feature in modern database engines called 'table elimination'. In order to handle changes in the information content Anchor Modeling emulates aspects of a temporal database in the resulting relational database schema. The earliest installations using Anchor Modeling were made in Sweden with the first dating back to 2004, when a data warehouse for an insurance company was built using the technique. In 2007 the technique was being used in a few data warehouses and one OLTP system, and it was presented internationally by Lars Rönnbäck at the TDWI (The Data Warehousing Institute) conference in Amsterdam.〔6th TDWI European Conference - (TDWI homepage )〕 This stirred enough interest for the technique to warrant a more formal description. Since then research concerning Anchor Modeling is being done in a collaboration between the creators Olle Regardt and Lars Rönnbäck and a team at the Department of Computer and Systems Sciences, Stockholm University. The first paper,〔 〕 in which Anchor Modeling is formalized, was presented at the 28th International Conference on Conceptual Modeling〔28th International Conference on Conceptual Modeling - (ER'09 homepage )〕 and won the best paper award. The research can be followed at (www.anchormodeling.com ), where material on Anchor Modeling is made public and free to use under a Creative Commons license. An online modeling tool is also available, which is free to use and Open Source. 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「Anchor Modeling」の詳細全文を読む スポンサード リンク
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