Report Models using Islookup and expandinline

I am building and deploying models.

I have many small description tables, they include two attributes. On attribute is the key (which is a code or type) and the other is a varchar description. They tables are each optionalone related to the primary table. I am "denormalizing" the description tables using Islookup. I change the Role in the primary table to ISLOOKUP, I modify the defaultattributes to remove the code or type key attribute, only the description attribute is now a detailattribute. I hide the key attribute just in case.

In most cases when I do this the description tables are denormalized and the user now sees only the description in the primary table in report builder. But in a few cases the key attribute (which is normally a code - 1, 2, 4, 5, etc) is displayed, it displays even though it is Hidden, ISlookup is defined and I remove it from the default attributes.

I don't know why some work and some don't, the relationships seem to be identical in my view. Is there something in the model that could designate a table can be used as a ISLookup?

To attempt to work around this I have tried using expandinline.

Any ideas?

Report Builder "honors" the Entity.IsLookup property in the UI if and only if the cardinality of the role used to reach the entity is One/OptionalOne, and the lookup entity has exactly one attribute in its IdentifyingAttributes collection.

|||the entity lookup property is one/optional one and there is only one identifying attribute, this is exactly the issue I have, it does not seem to be consistent. And I cannot find any other differences in the tables to help me understand why this is happening.|||There is one other minor constraint - the one identifying attribute must actually belong to the lookup entity (it cannot come from a related entity). Is this the problem?|||No, it does not come from a related table. I used expandinline and it looks good, if I only have the one identifying attribute I seem to get the correct result, anything I should be aware of?|||

If you use ExpandInline, the user will not be able to navigate to the lookup entity using the Advanced Explorer mode in Report Builder. This is useful when creating reports that compare an item to other items with the same lookup value.

It also sounds like you may have confused the DefaultDetailAttributes and IdentifyingAttributes collections on the lookup entity. For an entity to be treated as a lookup, the IdentifyingAttributes collection must have exactly one attribute in it. The contents of DefaultDetailAttributes is irrelevant.