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===<big>Database Models</big>=== | ===<big>Database Models</big>=== | ||
*'''Description''' | *'''Description''' | ||
| − | :The development and the exploitation of data models are the basic processes | + | :The development and the exploitation of data models are the basic processes that build the database engineeering domain. Models allow database structures to be described at the appropriate level of abstraction, so that schemas can be evaluated, transformed and reasoned about rigourously. They are at the core of design methodologies and CASE tools. The <b>conceptual models</b>, such as the Entity-relationship model and some interpretations of UML class diagrams aim at describing data/information structures at the conceptual, technology-independent level, while the many <b>logical models</b> (relational, object-relational, XML, and the like) currently available are intended to represent data structures as they are implemented by data managers (or by families thereof). |
:*<b>The SPHINX data models</b>. The SPHINX DBMS was based on a hierarchy of two data model. The first one would be qualified, according to the current terminology <i>conceptual</i> [P74-02] and the second one, <i>logical</i> [P74-01], though both were technology independent (I must confess that the titles of the paper are misleading!). The concept of technology-independent (PIM in the MDE vocabulary) logical model was popular in the seventies. This idea was later reused in the GAM, GER and DB-MAIN models. The SPHINX system and its data models are described in project reports [R78-01] to [R78-05]. | :*<b>The SPHINX data models</b>. The SPHINX DBMS was based on a hierarchy of two data model. The first one would be qualified, according to the current terminology <i>conceptual</i> [P74-02] and the second one, <i>logical</i> [P74-01], though both were technology independent (I must confess that the titles of the paper are misleading!). The concept of technology-independent (PIM in the MDE vocabulary) logical model was popular in the seventies. This idea was later reused in the GAM, GER and DB-MAIN models. The SPHINX system and its data models are described in project reports [R78-01] to [R78-05]. | ||
:*<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. This model emerged from hot discussions in a French-Belgian think tank [P74-03]. Hubert Tardieu, the architect of the Merise methodology, was a member of the team (though no co-author of [P74-03]). | :*<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. This model emerged from hot discussions in a French-Belgian think tank [P74-03]. Hubert Tardieu, the architect of the Merise methodology, was a member of the team (though no co-author of [P74-03]). | ||