What's the important constraints in project management in Oracle EBS implementation project?

in brief

Firstly scope . this should be finalized before project kick off. Any change in scope should come through change request .

then time - project delivery as per agreement 

then cost - by having sufficient resources will save costs

if above3 are managed effectively then implementation will be smooth . Otherwise the implementing company will bleed ..As the client/customer will try their best to manipulate with the scope. They will ask implementer to 

The Major constraint of the project management in EBS is finalizing the requirements and changes during the implementation process and also categorization of the scopes in the phases.