Significance of Secondary Entity in Plugin Registration Tool while Registering Plug-In in MSCRM

"Secondary Entity use when you have to trigger plugin or retrieve record from Intersect Entity(contactleads) having records of Entities(Contact and Lead) having N:N Relationship"

While using the Plugin Registration tool in Dynamics CRM, we might have rarely or even never used the ‘Secondary Entity’ field and almost always assigned it as ‘none’, but there are some scenarios where this field comes into play.

When is ‘Secondary Entity’ required

The following 2 messages require the ‘Secondary Entity’ to be specified while registering a step in Plugin registration:

• SetRelated
• RemoveRelated

These two methods were extensively used in Dynamics CRM 4.0, but they were deprecated from Dynamics CRM 2011 onwards; although you can still use them in 2011 and 2013.

What are the supported ‘Secondary Entities’

Following is the table depicting the out-of-the-box ‘Primary Entity’ and ‘Secondary Entity’ that are supported for both ‘SetRelated’ and ‘RemoveRelated’ messages:

Primary Entity	Secondary Entity	Supported Relationships
Invoice	Contact	contactinvoices_association
Lead	Account	accountleads_association
Lead	Contact	contactleads_association
Opportunity	Account	opportunity_customer_accounts
Opportunity	Contact	opportunity_customer_contacts
Opportunity	Competitor	opportunitycompetitors_associationor
Product	Lead	leadproduct_association
Product	Competitor	competitorproduct_association
Quote	Contact	contactquotes_association
SalesLiterature	Competitor	competitorsalesliterature_association
SalesLiterature	Product	productsalesliterature_association
SalesOrder	Contact	contactorders_association

You can also find this entire list in the Dynamics CRM SDK,

What does ‘SetRelated’ and ‘RemovedRelated’ do

These two messages are basically triggered when a primary entity record is associated/dissociated with/from the secondary entity record via the relationships supported, details of which are mentioned above. So, if you’re planning to execute some business logic on association of the above mentioned entities, you can register the plugin against the ‘SetRelated’ message. The ‘RemoveRelated’ works for dissociation of the entity records from each other.

From Dynamics CRM 2011 onwards, the ‘SetRelated’ and ‘RemoveRelated’ have been succeeded by the ‘Associate’ and ‘Disassociate’ messages respectively.