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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.
Consequently, the ER model becomes an abstract data model, [1] that defines a data or information structure that can be implemented in a database, typically a relational database. Entity–relationship modeling was developed for database and design by Peter Chen and published in a 1976 paper, [ 2 ] with variants of the idea existing previously ...
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.
An associative (or junction) table maps two or more tables together by referencing the primary keys (PK) of each data table. In effect, it contains a number of foreign keys (FK), each in a many-to-one relationship from the junction table to the individual data tables. The PK of the associative table is typically composed of the FK columns ...
To free the collection of relations from undesirable insertion, update and deletion dependencies. To reduce the need for restructuring the collection of relations, as new types of data are introduced, and thus increase the life span of application programs. To make the relational model more informative to users.
The computer can generate these accounts in real time using source document records. REA treats the accounting system as a virtual representation of the actual business. In other words, it creates computer objects that directly represent real-world-business objects. In computer science terms, REA is an ontology. The real objects included in the ...
Peter Pin-Shan Chen (Chinese: 陳品山; born 3 January 1947) is a Taiwanese-American computer scientist and applied mathematician.He is a retired distinguished career scientist and faculty member at Carnegie Mellon University and Distinguished Chair Professor Emeritus at Louisiana State University.
The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E. F. Codd in 1971. [2]Codd's definition states that a table is in 3NF if and only if both of the following conditions hold: