Merge two different applications into a single Application?

Please read this entire post thoroughly; and note that this is not a full-and-complete guide to this process; but it will help you prevent many pitfalls.

1.  As long as you are maintaining the original 2 Applications and essentially creating a 3rd independent application that is a combination of the 2 structures, then you can proceed with steps 2 onwards.  If you are not going to make unique copies of the two Applications; you must first document EVERY automation, webhook, QBAction, Table-to-Table Import and Email.  Make a copy of your 2nd Application so you can still reference the relationship structure and content of each one for each table.  

When you move tables from an Application; you will inevitably lose some relationships between the tables; so you need to have a structural-copy of the application before you start to reference and ensure everything is rebuilt/re-connected.

2.  Create an complete backup of all your data from both your Applications before you start anything.  You can use QuNect Backup Tool to do this (I recommend this to any Admin)

3.  Create a copy of the largest-application that has the most number of relationship connections - App A

4.  Create a copy of the other application App B

5.  Identify in App B what the different relationships are and try to identify from the Application Diagram which tables are children, versus parents

6.  From App A, strategically "move into this app" the child-tables from App B before the parent-tables

7.  Once all App B tables are in App A; go through each table thoroughly, referencing the original Application you copied.  Check the # of fields in each table are the same as your original application.  Rebuild the broken/missing relationships in each of the new tables moved from App B into App A.  You will lose some of your relationships; and will need to re-build not only the relationship but also all the Lookup fields and Summary fields in those relationships.  Your forms and reports will need to be updated to include these newly-rebuilt elements.

8.  In your new App A, reference each of your original Applications; go through every table carefully and thoroughly to review: 

1. ALL your Automations (you will have to completely rebuild these in App A for both App A and App B automations); 
2. Go through every table looking for Webhooks and update the endpoint URLs and new FIDS for rebuilt fields and remember to activate them.  
3. Go through every table checking your QBActions are correct and include all the fields for mapping.
4. Go through every table checking for Table-to-Table Imports and update them to point to the correct endpoints; and make sure the field mappings are up to date
5. Go through every table and review email notifications
6. Go through your formula-fields and check for hard-coded formulas that point directly to DBIDs and not table-Aliases - these will need to be updated as well
7. Go through your Pages (dashboards, code pages) and make sure any of them which point to an application dbid are pointing to the correct application
8. Check Home Pages for custom-link URLs that action functions or launch pages which are hardcoded URLs, not "links" to reports, pages etc.

Please know that this is list may not be complete; but will cover the majority of application elements you probably are not thinking about when copying and moving tables.  Make sure, whatever you do, that you document the Automations (these will NOT copy when create a copy of an Application)- and Quick Base backups do NOT include Automations.