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I can see that Extended Data Types can have Array Element which seems to make it a composite type. I'll be looking into that later.

What are the relations used for? MSDN was woefully crap at explainined what it would actually be used for. Why would you want to relate a type to a specific table and why would other tables using the type care?

William Mioch
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When I create a new 'PersonTable' table I could have a key field called personId, creating/using a new Extended Data Types called personId and adding the relation you've mentioned. Now when I add our EDT to other tables we do not have to specify either labels or relations to our PersonTable as this it's defined by the extended data type.

In a related form (e.g. PersonSkillsTable) where our personid field has been added to an existing table it will now automatically create the dropdown/grid to select a value from our persontable. We didn't need to add our persontable to the form's Data Source.

ian_scho
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  • And remember. The relationships between tables are defined at the 'business' level (i.e. in your code) and not as foreign keys in the database. It's a concept that I find difficult to comprehend but easy to utilise! – ian_scho May 19 '11 at 06:38
  • The relationship between tables is a business logic, so it does belong there. When you make foreign keys in the database you make a second business level and then a change is harder (having said that I don't like stored procedures as yet another business layer). I usually put foreign keys when developing, but it is only because it is another wall, which incompetent programmers will hit. – Bojan Milenkoski May 20 '11 at 17:57
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  1. Automatic relations between tables
  2. Automatic lookups
  3. Automatic "Go To Main Table" menu option after right-click
10p
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