I am trying to combine two Magento version 1 stores from separate domains. My goal is to combine the two existing sites into one so that it can be hosted on a new domain and after all the data is in one database run the migration tool to get to Magento version 2.
I have exported both stores live databases and imported one of them into a Docker instance (alexcheng/magento) so that I practice merging the data offline so that when I figure it out I can take the sites down for the actual merge and minimize down time.
MySQL Dump Database A and Merge Into Database B
When I try to take a mySQL dump of site A and import it to site B I am getting integrity check errors because they have conflicting primary/foreign keys. I believe that I can update the primary keys on database A by an offset before merging with Database B to overcome this issue. I believe that I need to cascade the changes so it updates all the foreign keys related to that primary key but I am unsure how to do this with many tables in the database.
Export Customers and Products from Magento Administrator Panel
I have read about exporting the Customers and Products to a CSV file from the Magento Administrator Panel. I believe that I can export site A to a CSV backup and then import to site B. I am worried that this will not retain order history.
Which solution would be more effective to merge all the data from both sites? Is there a better way that I am just overlooking? What resources would be best for me to research to achieve my end goal?
Thank you for taking the time to read this and help! This is my first post to any StackExchange site so if I haven't presented my problem properly please let me know and I will do my best to correct it.