Conceptual Diagram

In a general way, a conceptual diagram ( concept map in English) is a representation of a whole of concepts connected Sémantique lies between them. The concepts are connected by fléchées lines to which words are coupled. The relation between the concepts is based on terms expressing this one: “carries out to”, “prevents that”, “supports”, etc

The conceptual diagram works towards several ends. It makes it possible to represent the mental model of a situation, that this representation is personal, that of a group or an organization. It also makes it possible to summarize the structure of the knowledge extracted from written works.

The addition of objects of support: diagrams, reports/ratios, other diagrams, worksheet, etc, during the construction of diagrams would help learning how it to increase the quantity of information learned by the manufacturer. For this reason, with the 21e century, the teachers started to use these diagrams within the framework of their course.

In data processing, a conceptual diagram is a chart which is used to describe the operation of a Database. It thus represents the main objects contained in the latter, their characteristics and the relations which are established between these various objects. This representation is normalized according to a well defined modeling.

Several types of conceptual diagrams exist, correspondents with the various basic types of data which one can meet: the hierarchical model, semantic network models, the model entity/relation, the model object…

Hierarchical model

Information is organized in an arborescent way (according to a Hiérarchie), accessible only starting from the root of this tree structure.

The principal defect of this representation comes owing to the fact that the access point to information is quite single (it is the root of the hierarchical tree), from where problems in the search for information of the hierarchical Database.

Semantic Network models

This model describes the operation of a Database network.

This basic type of data functions on the principle of the regrouping of the various elements of the database by their direction. But, this model is too complex to be really effective.

All information can be associated the ones with the others and be used as access point.

Model Entity/Relation

The Entity-relation model (still called model Entity/Association) is a type of conceptual diagram very much used for the databases, in particular the relational databases.

Concepts

It is about a tool making it possible to describe the operation of the database while notifying:

the entities

These are concrete objects (delivers, individual) or abstract (bank account) that one can identify.
One can represent a whole of entities of reality by a standard entity (a pupil for the whole of the pupils).
These entities are characterized by their attributes (for the pupil: classify, name…). Among these attributes, one defines an identifier which will make it possible to characterize in a single way the entity as a whole (for the pupil, its name and first name can play this part).

Relations between the entities

They represent the bonds existing between one or more entities.
They are characterized by a name, a property of association and possibly of the attributes.

Degree of relation and cardinality

the degree of the relation (or dimension of the relation) is the number of entities which are implied in this relation. The relation can utilize only one entity, in which case it is known as reflexive.

Example of a reflexive relation: the relation “of marriage”

the cardinality (of an entity compared to a relation) expresses the number of possible participations of an entity in a relation. As it is a variable number, one notes the cardinality minimum (0 or 1) and maximum for each entity. For example, in a library, a user can borrow 0 or NR books, but the book can be borrowed only by 0 or 1 user.

Chart

the entities are represented in rectangles and are written in capital letters.
the identifier of an entity is the first quoted attribute and is underlined. The other attributes are placed after.
the relations are placed in ellipses or rhombuses with their respective attributes.
the cardinalities are placed beside the entity which they characterize.

Step of design

Here a possible method to carry out a diagram entity/relation:

To draw up the list of the entities
To determine the attributes of each entity by choosing an identifier
To establish the relations between the various entities
To determine the attributes of each relation and to define the cardinalities
To check the coherence and the relevance of the diagram obtained

Example: diagram entity/relation of a consultation in the doctor

Model Object

Within the framework of this model, the data are described like classes and are represented in the form of objects.

This diagram is often associated with the model entity/relation.

See too

Jacky Akoka and Isabelle Comyn-Wattiau, Design of the relational databases in practice (Chapter 1) , Vuibert 2001

External bonds

Free Concept Mapping Resources, gives working tracks to the teachers of the primary education
Advance organizers
Another approach of the conceptual diagram
, to seek through the Web
conceptual diagram Cours on the design of a conceptual diagram
'' How to build a conceptual diagram