Modern tool for import-export of data?

Question

PHP

What are the modern up-to-date solutions for data import and export?

• To save keys, links to related data
  
• To not store absolute keys
  

For example, there is a pack of data, a backup from the forum:

1. Users
   
2. Topics with links to users
   
3. Comments, with links to users and topics
   

The task is to upload and download in such a way that links are not lost, but at the same time absolute identifiers are not used so that the incremental case works.
Is it possible not to reinvent the wheel this time?
UPD. Can you at least tell me the format? The data is string, numbers and boolean. We need to keep the connections.