You are correct That SharePoint does not support relationships between your
tables for you.
On the other hand you might one explain why you're moving these tables to
SharePoint in the first place? What is your goal here?
Because SharePoint does not support a number of features in access when you
move those tables up to SharePoint then for applications that have a good
number of related tables that your application requires to function
correctly with,
for the most part using SharePoint is likely not a good idea here.
On the other hand if your application only had say perhaps 1 or 2
related tables, then it's only a couple extra lines of code in your
application that you have to add that will delete the child records
when you need to delete a customer name for example.
In other words if you're moving your data tables to SharePoint, then you
must have considered that the advantages of SharePoint will outweigh the
additional work it will take to make your application function correctly.
In other words for applications that only have one table, then the decision
to use SharePoint in this case is often very easy. After you upsize that
table to SharePoint, then people all across the country can have the
access application installed on their computers, and even with wireless
Internet connections, they'll all be sharing the data in multi user mode.
On the other hand for applications that have many tables, are reasonably
complex, and have many relationships, then it makes sense to upsize your
tables to SQL server and not SharePoint. The reason being in this case is
many, but one significant issue is that as your application becomes more
complex, and actually becomes less work to move everything up to SQL server
because SQL server is designed and built to handle those relationships.
However, at the end of the day simply moving tables to sharepoint, or moving
it to SQL server is a big decision that requires some planning and analysis
on your part as to which is a better choice, or if your tables and data
should remain inside of ms-access.