Apply business logic using code
Whenever possible, you should first consider applying one of the several declarative process options to define or apply business logic. More information: Apply business logic in Common Data Service
When a declarative process doesn’t meet a requirement, as a developer you have several options. This topic will introduce common options to write code.
Create a plug-in
You can write a .NET assembly to plug-in to the data transaction to apply business logic on the server. With Common Data Service there is a framework you use to register specific events to execute code defined within a class in an assembly.
More information: Write plug-ins to extend business processes
Create a workflow extension
You can write a .NET assembly to provide new options within the process designer. This method provides a new option for people using the workflow designer to apply a condition or perform a new action. A workflow extension can then be re-used by people who are not developers to apply the logic in your code.
More information: Workflow extensions