Bx Examples Repository
Title: Conceptual schema to multiple logical schemas
Version: 0.1
Type: Sketch
Overview
The EU Horizon 2020 project Typhon has the example of a distributed data storage system. A single conceptual model (CM) links to many different components including relational and no-SQL databases, file stores, etc. Each component has its own logical schema (LS_i) using the internal concepts of that component (e.g. relational db - relational schema; rbd tables, rdbms types and operations, etc.). However, to determine whether pairs, triples … (up to all LS_i) of LS_i are consistent requires reference to the CM, which abstracts the relationships between all concepts.
Models
Suppose we have one conceptual schema (CM) which is supposed to be represented using a collection of logical schemas (LS_1, LS_2, LS_3, LS_4, LS_5).
Consistency
The multidirectional consistency relation is to be: every entity in the conceptual schema is to be present in exactly one logical schema while every binary relation in the logical schema must be present either in one of the logical schemas, if both its ends are in the same one, or between two, if its ends are represented in different logical schemas.
Consistency Restoration
There is a bx between each LS_i and CM, which maintains consistency between CM and LS_i. In particular, R_e is the relation concerning data entities, whereas R_a is the relation concerning the management of data attributes. However, to determine whether pairs, triples … (up to all LS_i) of LS_i are consistent with respect to R_a requires reference to the CM, which abstracts the relationships between all concepts. Thus, consistency between LS_1 and LS_2 references CM to establish how concepts in each LS_i are related in the overall system. This is a multx.
Discussion
See below.
References [optional section]
The example comes from the EU H2020 Typhon project (https://www.typhon-project.org/). No bibliographic references yet.
Author(s)
Davide Di Ruscio, Fiona A.C. Polack, Martin Gogolla, Anthony Cleve, Dominique Blouin, Nuno Macedo
Reviewer(s)
none yet
Comments
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Artefacts [optional section]
Formal descriptions, perhaps downloadable code, example inputs and outputs, virtual machine instances, diagrams…