The goal is if both features are installed, the default verb for .FOO is to edit with the Editor component and a Secondary verb is to view it with the Viewer component.
If only the Viewer feature is installed, viewing with the viewer component should be the default action.
Is this possible with MSI? The schema is confusing me. The extension table has PK columns of Extension and Component_. This suggests to me that a file extension can be served by multiple providers.
But the verb table has PK columns of Extension_ and Verb. This almost makes sense as a file extension can have multiple verbs.
But what is confusing me is how do I associate the verb to the correct component? The SDK doco makes reference to "the component that owns the verb." but there is no join to the component table and the join via the extension table seems ambigious.
If you have a record in the Verb table that links to a foreign key in the Extension table, the Extension table record contains the component and feature association used to register the verb at runtime (the relationship to feature/component is indirect; the Registry Table Group diagram may help). Multiple Verb table entries using the same Extension foreign key would have the effect of being associated to the same feature/component. The verb with the lowest sequence number will become the default verb for the extension (although it is unclear if this works when different verbs for the same extension are in different components).
You can use the Advanced Settings|File Types view available for each component in the Setup Design or Components view to abstract the table information into something a little easier to understand.
The limiting factor does appear to be the Verb table. It is possible to have the same extension across multiple components in the Extension table, but attempting to use the same extension and verb in the Verb table will duplicate primary keys. The tables probably are designed this way for advertisement purposes (a given product code/feature/component code/keyfile combination can only be used once). The Extension table does impose a similar limitation by only allowing one extension/component combination with a given feature; anything beyond the one combination will duplicate primary keys.
The simplest solution to this issue would likely be to use the Registry table to create the extension and verb keys per component.
