منابع مشابه
Orm 2
Object-role Modeling (ORM) is a fact-oriented modeling approach for specifying, transforming, and querying information at a conceptual level. Unlike Entity-Relationship modeling and Unified Modeling Language class diagrams, fact-oriented modeling is attribute-free, treating all elementary facts as relationships. For information modeling, fact-oriented graphical notations are typically far more ...
متن کاملTemporal Modeling and ORM
One difficult task in information modeling is to adequately address the impact of time. This paper briefly reviews some popular approaches for modeling temporal data and operations, then provides a conceptual framework for classifying temporal information, and proposes data model patterns to address time-impacted tasks such as modeling histories, and tracking entities across time as they migrat...
متن کاملORM in Detail
Object-Role Modeling (ORM) is a method for modeling and querying an information system at the conceptual level, and mapping between conceptual and logical (e.g. relational) levels. ORM comes in various flavors, including NIAM (Natural language Information Analysis Method). This article provides an overview of ORM, and notes its advantages over Entity Relationship and traditional Object-Oriented...
متن کاملReasoning in ORM Schemes
In this research, First, we propose nine patterns of constraint contradictions that lead to unsatisfiability in ORM. Although this does not yield a complete procedure – there may be ORM schemes passing the pattern checks while containing unsatisfiable roles – it yields an efficient and easy to implement detection mechanism (specially in interactive modeling tools) for the most common conceptual...
متن کاملReduction Transformations in ORM
This paper proposes extensions to the Object-Role Modeling approach to support schema transformations that eliminate unneeded columns that may arise from standard relational mapping procedures. A “unique where true” variant of the external uniqueness constraint is introduced to allow roles spanned by such constraints to occur in unary fact types. This constraint is exploited to enable graphic p...
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ژورنال
عنوان ژورنال: Nature Reviews Molecular Cell Biology
سال: 2010
ISSN: 1471-0072,1471-0080
DOI: 10.1038/nrm2875