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===Database Models=== | ===Database Models=== | ||
*'''Description''' | *'''Description''' | ||
| − | :The development and the exploitation of data models are at the | + | :The development and the exploitation of data models are at the baseline of the database engineeering domain. They allow database structures to be described at the appropriate level of abstraction, so that one can rigourously evaluate and transform schemas and reason about them. They are at the core of design methodologies and CASE tools. The <b>conceptual models</b>, such as the Entity-relationship model and some interpretation of UML class diagrams are aimed at describing data/information structures at the conceptual, technology-independent level, while the many <b>logical models</b> currently available are intended to represent data structures as they are implemented by data managers (or by families thereof). |
:*<b>The Individual model</b>. Reference [P74-04] reports on the first version on the Individual model (a variant of the ER model), which was the main component of the MERISE methodology. Hubert Tardieu, the architect of the Merise methodology was a member of the team. | :*<b>The Individual model</b>. Reference [P74-04] reports on the first version on the Individual model (a variant of the ER model), which was the main component of the MERISE methodology. Hubert Tardieu, the architect of the Merise methodology was a member of the team. | ||
:*<b>The GAM</b>. | :*<b>The GAM</b>. | ||
:*<b>The GER model</b>. The Generic Entity-relationship model (GER) is a wide-spectrum information/data structure specification model. Encompassing the main concepts and constructs of most popular modeling formalisms, be they value-based or object-based, it has been given a precise semantics via an extended version of the NF2 (non-first normal form, or nested) relational model [6]. Through a specialization mechanism, such usual models as ERA, UML class diagram and ORM can be rigourously specified and compared [7]. Similarly, the GER can be used to define standard data models such as the relational, object-relational, CODASYL, IMS, XML or plain file structure models. | :*<b>The GER model</b>. The Generic Entity-relationship model (GER) is a wide-spectrum information/data structure specification model. Encompassing the main concepts and constructs of most popular modeling formalisms, be they value-based or object-based, it has been given a precise semantics via an extended version of the NF2 (non-first normal form, or nested) relational model [6]. Through a specialization mechanism, such usual models as ERA, UML class diagram and ORM can be rigourously specified and compared [7]. Similarly, the GER can be used to define standard data models such as the relational, object-relational, CODASYL, IMS, XML or plain file structure models. | ||
| − | :*<b>The DB-MAIN model</b>. | + | :*<b>The DB-MAIN model</b>. This model is a partial implementation of the GER. It has been developed for the DB-MAIN CASE environment. A precise definition can be found in the DB-MAIN manuals and in DB design tutorials . |
| − | :*<b>Temporal data models</b> [P01-02] | + | :*<b>Temporal data models</b>. [P01-02] |
*'''Keywords''' | *'''Keywords''' | ||
:ER model, Invidual model, wide-spectrum model, GER model, logical data model, temporal model, network model, hierarchical model, OO model, large schema layout, semantic and statistical aspects of models, IS-A relations | :ER model, Invidual model, wide-spectrum model, GER model, logical data model, temporal model, network model, hierarchical model, OO model, large schema layout, semantic and statistical aspects of models, IS-A relations | ||
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