Setting up relational database

Indeed. Thank you for the reminder and for your earlier post.

I am still uncanning worms, but I suppose that is the beginner’s diet.

I have set up three databases: dbA, dbB, & dbC (not the actual names, in case that signifies).
Each database has more than one field.
Each database has one field called “UniqID” (again, not the actual name).

My goal is to have the value of the UniqID of the current record written into the UniqID fields of a newly-created record in dbB and in dbC when I enter text in the UniqID field of dbA.

I have the following code in the Code field of the Field Properties of dbA’s UniqID field:
post "updateadd", "dbB", "UniqID", UniqID, "UniqID", UniqID

(I should state that dbA has a .newrecord procedure, as I have been working in all available directions. That procedure now consists of several lines commented-out, and one statement: addrecord.)

When I add a new record to dbA and enter text in the UniqID field and tab out of the field, a new record is created in dbB, but it is blank.

I get the same result when I specify dbC instead of dbB.

If I change the code to:
post "updateadd", "dbB", "UniqID", UniqID, "UniqID", "Catfish"
when enter text in the UniqID field in dbA and tab out of the field, a new record is created in dbB, it is blank, and “Catfish” replaces the text I typed in the UniqID field of dbA. This strikes me as irregular, and therefore significant.

I get the same result when I specify dbC instead of dbB.

Further, when I tried to create a new record with UniqID copied from dbA to each of dbB and dbC with the following two lines of code:
post "updateadd", "dbB", "UniqID", UniqID, "UniqID", UniqID
post "updateadd", "dbC", "UniqID", UniqID, "UniqID", UniqID
a new blank record was created in dbB, and a new record was created in dbC, with the UniqID field containing the UniqID value from the UniqID field of dbA!

When I reverse the order of the two lines of code, the result is reversed: a blank new record in dbC and a new record in dbB with the value of UniqID in dbA in the UniqID field of dbB.

I see similar results with the post statement when used (sort of) as @admin recommends elsewhere in this thread. With the following in the code field of the UniqID field of dbA:
let theID=UniqID
post "add","dbB","","","UniqID",theID
A new record is created, and it is blank.

(I tried this in the .NewRecord procedure*, but it doesn’t do what I need, since the new record in dbB is created at the same time as the new record in dbA, and therefore there is no value in the UniqID field of dbA. I understand that the suggestion to use a .NewRecord procedure was based on automatically generating UniqID values. I could, perhaps, do it this way, but it entails adding a whole other set of fields to the databases, which I could hide, but it seems a long way 'round. I will always need a unique person-reference that brings to mind the person. I had thought a simple solutions would be to assign these myself, and use them in lieu of any alpha-numeric code.)

(@admin Jim — especial thanks for the link and exact volume and page in the Pan6 documents regarding the .NewRecord procedure.)