I believe the scenario is common mostly in business workflows - for example: loan management

the process starts with a loan application, then there's the loan offer, the 'live' loan, and maybe also finished loans.

• all these objects are related, and share many fields
• all these objects have also many fields that are unique for each entity
• the variety of objects maybe large, and the transformation between the may not be linear (for example: a single loan application may end up as several loans of different types)

How would you model this?

some options:

• an entity for each type, each containing the relevant fields (possibly grouping related fields as sub entities) - leads to duplication of data.

• an entity for each object, but instead of duplicating data, each object has a reference to it's predecessor (the loan doesn't contain the loaner details, but a reference to the loan application) - this causes coupling between the object structure, and the way it was created. if we change the loan application, it shouldn't effect the structure of the loan entity.

• one large entity, with fields for the whole life cycle - this can create 'mega objects' with many fields. it also doesn't work well when there's a one to many or many to many relation between the phases.