entity-relationship model

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entity-relationship model

(database, specification)
An approach to data modelling proposed by P. Chen in 1976. The model says that you divide your database in two logical parts, entities (e.g. "customer", "product") and relations ("buys", "pays for").

Entity-relationship diagrams can be used to represent a model.

["The entity-relationship model: toward a unified view of data", P.P. Chen, ACM Transactions on Database Systems 1:1 pp 9-36, 1976].
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References in periodicals archive ?
The method of applying the calculus of descriptive logics for identifying conflicts of entity-relationship conceptual schemes of relational databases allows us to reduce the process of identifying of semantic conflicts of metadata and the inconsistency of data which occurs when their integration, to solving of algorithmic problems of consistency and classification of terminology, and the consistency of the ontology of these data [7; 14; 15].
The entity-relationship model - toward a unified view of data.
(26) Robert Maxwell has provided a much more detailed discussion, which treats diagramming methods for entity-relationship models, comparing Chen's system and those used in FRBR and FRAD, and then moves to a consideration of the FRBR entities, relationships, and user tasks, ending with a comparison between the FRBR model and catalogue records produced under AACR2.
Let us briefly review the key definitions of Entity-Relationship schemata following [18].
Conceptual database design: an Entity-relationship approach.
Entity-relationship modeling, which "divides a given data universe (e.g., the data required to run a business) into specific entities linked by specific relationships," is the key to FRBR, he says.
A third trace of connectedness in existing organization of information practice is the emerging use of the entity-relationship model, most notably in the Functional Requirements for Bibliographic Records (FRBR) (IFLA Study Group on the Functional Requirements for Bibliographic Records [IFLA], 1998), but also in the increased use of XML and RDF for encoding metadata.
SQL-Tutor teaches the SQL query language, NORMIT is a data normalization tutor, and KERMIT teaches conceptual database modeling using the Entity-Relationship data model.
Codd's ideas on relational systems (1970, 1972b) and syntactic normalization (1972a) had proven superior in most conceptual and logical respects to the older classes of implementation platforms such as network and hierarchical systems, and Abrial's (1974) paper had signaled the advent of the semantic database era that would culminate soon thereafter with the publications of Chen's (1976) entity-relationship model and Smith and Smith's (1977) data abstraction ideas.
Figure 1 illustrates an Entity-Relationship diagram that expresses a relationship (prefers) between two entities: customer and product.
Codd also objects to the entity-relationship model on the grounds that it does not allow associations to have properties.
HDM-lite descends from the Entity-Relationship Model [Chen 1976] and from HDM [Garzotto et al.