Convert to Auto Through Entity command does not appear on right-click menu

[Posted on behalf of a customer]

I was able to create the through association and choose the through entity. However I would like to somehow set it up as an auto-through entity, but I cannot work out how to do that. In the docs it says:
 
"If you have an explicit through entity and it’s not adding any value, you can convert it to an auto through entity by right-clicking the through association and choosing Convert to Auto Through Entity."
 
But after I have gotten it all mapped, right clicking the association does not show that option? I don’t need the join table mapped to my model at all, just the through association.

We show the "convert to auto through entity" command only if:

* The through entity has no properties of its own (only the two one-to-many associations)
* The through entity is not using a composite key

Many databases use a composite key for through tables instead of having a separate Id column plus the two foreign keys.  Could that be the case in your database?  Such tables have to be represented as explicit through entities in LightSpeed -- auto through entities are only for tables that adhere to the LightSpeed convention of having a separate Id.

Yes, that is exactly the case. The only values in the join table are the foreign keys, and as such they are also the primary keys. The table is a pure join table, so there is zero value at all in having the entities mapped (and needing the corresponding one-to-many associations to the through entity at all).

Can I request that support for a pure through entity be made available if you are using a pure join table? That is how it is supported in all the other ORM's I have been working with, and conceptually adding an extra ID value to the tables complicates and muddies the concept. If the foreign keys used in the join table are not considered part of the primary key, you then need to add other constraints on the table to ensure that you cannot ever have a duplicate entry, since that would be meaningless in a many-to-many association. Not to mention it just adds more data to the resulting tables making the storage requiments bigger.

I have it working for the moment, but it just seems ugly to me to either a) have the entity mapped when it is not necessary or b) have a separate id column for that table.