Why is Key Attribute mandatory in Attribute View?
I am curious about the behavior of key attributes in attribute views.
First I thought it is kind of primary key for the entity Attribute View but then I did a few checks
Created two tables
1. CUST -Customer Table- It has Customer ID and Country ID
2. CTRY -Country Table- It has Country ID and Country Description
An Attribute View on top of these two tables
Simple, nothing complex
Now in Semantics
I am able to activate the attribute view and see the output
but what I do next is interesting..I made the CID as a Key Attribute, though it is not a key in the data ('in' for two rows)
But I am still able to activate the Attribute View and see the data as well. I would like everyone to try this out.
So what I don't understand is if this is allowed why is Key Attribute Mandatory?
I mean why should there be a key attribute if it does not check for Unique Constraint.