Question : How do I teach Young People Data Modelling ?
Database Answers has a Tutorial on Data Modelling for Young People
Question : What is the difference between Conceptual, Logical and Physical Data Models ?
Wikipedia has some useful entries on Conceptual Models, Logical Models and Data Models.
Conceptual Data Models do not conventionally show Foreign Keys and are very useful for 
making clear the Entities and Relationships in a Data Model without any Keys or Attributes.
They are very useful for discussing Requirements with Users because they show only the basics.
Logical Data Models add Foreign Keys and Attributes.
They are very useful for publishing a complete statement of the data involved.
Physical Data Models are very close to the Database design.
They are very useful for discussions between the Data Analyst, DBAs and developers.
Question : What is an Information Catalogue ?
An Information Catalogue can play a very important role in Data Integration.
It can also be called a Data Dictionary or an Information Repository.
Wikipedia has an entry for a Data Dictionary that is worth checking out.
Wikipedia also has an entry for Information Repository which describes something different.	
An Information Catalogue can be used to record every activity and decision of importance relating to Data Integration at each Stage.
It can play a role from the beginning, by recording Data Owners and Data Sources.
Then during the Data Integration Stage, it can record details of Tables, Fields, Rules for Validation, Mapping and Translation.
In the Reporting Stage, it can be used to record definitions of Report Templates and specific variations of the Templates for specific Projects.
In the Data Governance Stage, it can be used to record decisions and agreements reached in critical aspects of Data Management.
The best use of the Information is to be deployed over an Intranet and/or in the Clouds so that individuals throughout an organization 
can share the Information, comment on issues and so on.
Some commercial products are available, listed here alphabetically :-
•	ASG Rochade “The world’s leading Metadata Repository” –
•	Computer Associates Repository for Distributed Systems
•	IBM Repository
•	IBM SOA Repository
•	Oracle Enterprise Repository
•	Unisys used to market a product called Universal Repository but a search of their Web Site revealed nothing, except that 
Sybase acquired the rights to it back in 1998. 
The selection of a commercial product should include the ability to exchange data and metadata.
This can be achieved by XMI or by the SQL that creates the Tables.

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