Connecting dataverse tables via multi fields

[cshinneman]

My schema requires I use multi-element access between tables...  (ie. Company+Employee) not an uncommon database problem.  Power Apps allows you can create multi-field keys but does not allow you to use then in model-driven development.  

I read that one method is to create a calculated field and concatenate the fields into that.  but the CONCAT() function does not work with fields that are either LOOKUP or  CHOICE.

[HSheild · Accepted solution]

Hi @cshinneman 

Have you tried the Concat function using a string field from the Lookup? I.e. here are the instructions from Microsoft docs

You can access parental columns via the Lookup column to the parent table, such as <LookupFieldName>.<FieldName>

[cshinneman]

This worked great in getting a calculated field that was a concatenation of two fields.  Thank you!

Now I am attempting to use that field as a lookup in the child table.  It works in a very odd way.  In one instance it brings in the locally defined field (of the calculated column) in the parent table but on the looked-up field in the parent.  In another case the parent table shows as a popup table but when a record is selected no data is copied into the child field.  In another case  where the parent calculated field is composed of two lookup fields no popup table shows at all.