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Crow's foot notation, the beginning of which dates back to an article by Gordon Everest (1976), [16] is used in Barker's notation, Structured Systems Analysis and Design Method (SSADM), and information technology engineering. Crow's foot diagrams represent entities as boxes, and relationships as lines between the boxes.
The entity–relationship model proposes a technique that produces entity–relationship diagrams (ERDs), which can be employed to capture information about data model entity types, relationships and cardinality. A Crow's foot shows a one-to-many relationship. Alternatively a single line represents a one-to-one relationship. [4]
Barker's notation refers to the ERD notation developed by Richard Barker, Ian Palmer, Harry Ellis et al. whilst working at the British consulting firm CACI around 1981. The notation was adopted by Barker when he joined Oracle and is effectively defined in his book Entity Relationship Modelling as part of the CASE Method series of books.
IDEF1X, IE (Crow’s feet), UML, and more Yes Yes Update database and/or update model No Navicat Data Modeler Conceptual, Logical & Physical IE (Crow’s foot) Yes Yes Update database and/or update model No NORMA Object-Role modeling Conceptual (ORM), Logical, Physical ORM, Relational(Crow’s foot option), Barker Yes Yes
Three levels of view are defined in IDEF1X: entity relationship (ER), key-based (KB), and fully attributed (FA). They differ in level of abstraction. The ER level is the most abstract. It models the most fundamental elements of the subject area - the entities and their relationships. It is usually broader in scope than the other levels.
I have added a section entitled Alternative diagramming conventions with a diagram and explanation for Crow's Feet notation. I encourage you all to post up similar descriptions of the notations you prefer. See also Diagram is not standard section below. --Matthew 1130 13:05, 30 December 2006 (UTC)
An entity–relationship model (ERM) is an abstract conceptual representation of structured data. Entity–relationship modeling is a relational schema database modeling method, used in software engineering to produce a type of conceptual data model (or semantic data model ) of a system, often a relational database , and its requirements in a ...
The enhanced entity–relationship (EER) model (or extended entity–relationship model) in computer science is a high-level or conceptual data model incorporating extensions to the original entity–relationship (ER) model, used in the design of databases.