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.
The EER model includes all of the concepts introduced by the ER model. Additionally it includes the concepts of a subclass and superclass (Is-a), along with the concepts of specialization and generalization. Furthermore, it introduces the concept of a union type or category, which represents a collection of objects that is the union of objects of different entity types. The EER model also includes EER diagrams that are conceptual models that accurately represent the requirements of complex databases.
Subclass and superclassedit
Entity type Y is a subtype (subclass) of an entity type X if and only if every Y is necessarily an X. A subclass entity inherits all attributes and relationships of its superclass entity. This property is called the attribute and relationship inheritance. A subclass entity may have its specific attributes and relationships (together with all the attributes and relationships it inherits from the superclass). A common superclass example is a Vehicle superclass along with the subclasses of Car and Truck. There are a number of common attributes between a car and a truck, which would be part of the superclass, while the attributes specific to a car or a truck (such as max payload, truck type...) would make up two subclasses.
Toolsedit
This section needs expansion. You can help by adding to it. (November 2012)
The MySQL Workbench offers creating, editing and exporting EER Models. Exporting to PNG and PDF allows easy sharing for presentations.
Skipper allows users to create, import and export from object–relational mapping (ORM) schema definitions to editable EER models.
SAP PowerDesigner[3] is a complex tool for modelling and transforming different models.
Textbooks discussing EER and implementation using purely relational databases:
Elmasri, Ramez; Navathe, Shamkant B. (2011). Fundamentals of Database Systems (6th ed.). Pearson/Addison Wesley. Chapters 8 and 9. ISBN978-0-136-08620-8.
Coronel, Carlos; Morris, Steven; Rob, Peter (2011). Database Systems: Design, Implementation, and Management (9th ed.). Cengage Learning. Chapter 5. ISBN978-0-538-46968-5.
Connolly, Thomas M.; Begg, Carolyn E. (2005). Database Systems: A Practical Approach to Design, Implementation, and Management (4th ed.). Addison-Wesley. Chapters 12 and 16. ISBN978-0-321-21025-8.
Booklet discussing EER and implementation using object-oriented and object–relational databases:
Dietrich, Suzanne W.; Urban, Susan D. (2011). Fundamentals of Object Databases: Object-Oriented and Object–Relational Design. Morgan & Claypool Publishers. ISBN978-1-60845-476-1.
Textbook discussing implementation in relational and object–relational databases:
Teorey, Toby J.; Yang, Dongqing; Fry, James P. (1986). "A logical design methodology for relational databases using the extended entity–relationship model". ACM Computing Surveys. 18 (2): 197–222. CiteSeerX10.1.1.105.7211. doi:10.1145/7474.7475.
Sikha Bagui (2006). "Extended Entity Relationship Modeling". In Laura C. Rivero; Jorge H. Doorn; Viviana E. Ferraggine (eds.). Encyclopedia of Database Technologies and Applications. Idea Group Inc (IGI). pp. 233–239. ISBN978-1-59140-795-9.
External linksedit
[1] - Slides for chapter 8 from Fundamentals of Database Systems by Elmasri and Navathe (Pearson, 2011)
[2] - Lecture notes from the University of Toronto
enhanced, entity, relationship, model, enhanced, entity, relationship, model, extended, entity, relationship, model, computer, science, high, level, conceptual, data, model, incorporating, extensions, original, entity, relationship, model, used, design, databa. 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 It was developed to reflect more precisely the properties and constraints that are found in more complex databases such as in engineering design and manufacturing CAD CAM telecommunications complex software systems and geographic information systems GIS 1 2 Contents 1 Mechanics 1 1 Subclass and superclass 2 Tools 3 See also 4 References 5 Further reading 6 External linksMechanics editSee also Entity relationship model and Unified Modeling Language The EER model includes all of the concepts introduced by the ER model Additionally it includes the concepts of a subclass and superclass Is a along with the concepts of specialization and generalization Furthermore it introduces the concept of a union type or category which represents a collection of objects that is the union of objects of different entity types The EER model also includes EER diagrams that are conceptual models that accurately represent the requirements of complex databases Subclass and superclass edit Entity type Y is a subtype subclass of an entity type X if and only if every Y is necessarily an X A subclass entity inherits all attributes and relationships of its superclass entity This property is called the attribute and relationship inheritance A subclass entity may have its specific attributes and relationships together with all the attributes and relationships it inherits from the superclass A common superclass example is a Vehicle superclass along with the subclasses of Car and Truck There are a number of common attributes between a car and a truck which would be part of the superclass while the attributes specific to a car or a truck such as max payload truck type would make up two subclasses Tools editThis section needs expansion You can help by adding to it November 2012 The MySQL Workbench offers creating editing and exporting EER Models Exporting to PNG and PDF allows easy sharing for presentations Skipper allows users to create import and export from object relational mapping ORM schema definitions to editable EER models SAP PowerDesigner 3 is a complex tool for modelling and transforming different models See also editObject relational database Slowly changing dimension Structured typeReferences edit Enhanced Entity Relationship Model jcsites juniata edu Retrieved 2017 10 09 Elmasri Ramez Navathe Shamkant B 2015 Fundamentals of database systems Seventh ed Pearson p 1280 ISBN 978 0133970777 SAP PowerDesignerFurther reading editTextbooks discussing EER and implementation using purely relational databases Elmasri Ramez Navathe Shamkant B 2011 Fundamentals of Database Systems 6th ed Pearson Addison Wesley Chapters 8 and 9 ISBN 978 0 136 08620 8 Coronel Carlos Morris Steven Rob Peter 2011 Database Systems Design Implementation and Management 9th ed Cengage Learning Chapter 5 ISBN 978 0 538 46968 5 Connolly Thomas M Begg Carolyn E 2005 Database Systems A Practical Approach to Design Implementation and Management 4th ed Addison Wesley Chapters 12 and 16 ISBN 978 0 321 21025 8 Booklet discussing EER and implementation using object oriented and object relational databases Dietrich Suzanne W Urban Susan D 2011 Fundamentals of Object Databases Object Oriented and Object Relational Design Morgan amp Claypool Publishers ISBN 978 1 60845 476 1 Textbook discussing implementation in relational and object relational databases Ricardo Catherine 2011 Databases Illuminated 2nd ed Jones amp Bartlett Publishers Chapter 8 ISBN 978 1 4496 0600 8 Shorter survey articles Teorey Toby J Yang Dongqing Fry James P 1986 A logical design methodology for relational databases using the extended entity relationship model ACM Computing Surveys 18 2 197 222 CiteSeerX 10 1 1 105 7211 doi 10 1145 7474 7475 Sikha Bagui 2006 Extended Entity Relationship Modeling In Laura C Rivero Jorge H Doorn Viviana E Ferraggine eds Encyclopedia of Database Technologies and Applications Idea Group Inc IGI pp 233 239 ISBN 978 1 59140 795 9 External links edit 1 Slides for chapter 8 from Fundamentals of Database Systems by Elmasri and Navathe Pearson 2011 2 Lecture notes from the University of Toronto 3 The ER Conference nbsp This database related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Enhanced entity relationship model amp oldid 1168566439, wikipedia, wiki, book, books, library,
