Importing data as part of an implementation if a fact of life. When AX2012 original came out there was a couple of features that were not the same as they were previously in AX2009 for example the Excel based import capabilities and the data import definition group concept. A new data migration framework was released in beta format for R1 and then updated a few times by the time we got to AX2012 R2 CU7 there was a decent amount of functionality included in the framework.
The data migration framework uses an entity concept to move and validate data. This gives you the ability to manage related data that wasn’t in the previous generation of data import options. I sometimes hear complaints from customers that there isn’t an entity for everything in AX. I have to look back to previous version and say well it’s a lot better than what we had in the past as there were not concepts of entities in the past it was up to the implementation to work out the relationships. At least in the current version up to AX2012R2 CU7 and AX2012 R3 there is now a good amount of entities coverage for common entities that would need to be migrated in a typical implementation. If there isn’t an entity out of the box then you can either create your own or also use the table entity. This video gives you an overview of the concepts in the data migration framework and show how to create an entity with the wizard and using the entity and the table entity.
There are around ~150 entities in the AX2012 R3. Each entity could be one of many tables. And this covers typical master data like customer, vendor, product, BOM, fixed asset etc and transaction documents like journals, purchase order, sales order. Where there is typically work building entities is customized entities or ISV solutions. Long and short while there can also be improvements we certainly have a jump up in capabilities from prior versions. Having said that there are still some capabilities in prior versions of AX like copy company which were very handy in managing configuration data for implementation, test and training that we are still waiting to get back.