Summary
Creating many-to-many relationships with Marketo custom objects requires an intermediary object with one link to a Lead or Company and another link to a secondary custom object. Here's how to solve the problem of the secondary custom object not showing up to be selected as the linked object.
Issue
Creating a many-to-many or N:N custom object structure such that a lead or company can be associated with multiple custom objects and a custom object can be associated with multiple leads or companies at the same time. When adding a link to the secondary custom object, that secondary object is not list as an available linked object.
Solution
If you find that the custom object you'd like to link to is not list in the "Link Object" list, there are two things two check:
- The secondary CO must be approved.
- The secondary CO must not have any link type fields.
Since it's not possible to change a link field once a custom object is approved, if you already have link fields, the only solution is discard the secondary custom object and create a new one. Recreate the custom object without link fields. Then, in the intermediary object, the target object will show up as an available link object.
More detail can be found at:
Root Cause
The secondary custom object type is not approved.
- or -
The secondary custom object type is approved type and has link fields.
Environment
Marketo Custom Objects Many to Many Relationship - N:N Link Fields
.png)