Page Comparison

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1. Data Object Class

The entity's DO class must implement ICRMDOApprovalEntity interface and its twelve methods: 

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In entities metadata file, <approvalincluded> tag's value must be set to true. Keep in mind that <approvalincluded> default value is false.

<entities>
	<entity>
		<id>CUSTOMRENTALS</id>
		<name>key_rental</name>
		<tablename>TRN_RENTALS</tablename>
		<classname>com.crm.dataobject.rentals.CUSTOMCRMDORental</classname>
		<moduleid>CUSTOM_RENTALS</moduleid>
		<metadatafile>rentals</metadatafile>
		<approvalincluded>true</approvalincluded>
	</entity>
	...
</entities>

Note that approvals are triggered only through Workflow Rules, and therefore there is no point for an entity to be an Approval Entity without being a Workflow Rule Entity.