By what field are the regions in KLADR connected to the city?

Question

Database

Good afternoon!
Tell me, how is communication between cities and regions in KLADR organized?
The KLADR.DBF file contains cities, regions, and other objects. The fields in the database are:
Id, NAME, SOCR, CODE, GNINMB, UNO, OCATD
The CODE field contains the "Object Code". For the Volgograd region, it is equal to "3400000000000". If we cut off all zeros on the right and make an SQL query like
SELECT NAME FROM BaseName WHERE SOCR='r' AND CODE LIKE '34%'
then we will get the cities of the Volgograd region. The same is true for many other cities and regions.
But at the same time, Moscow's "CODE" field is equal to 7700000000000, and the Moscow region's "CODE" field is equal to 5000000000000. Serpukhov, for example, has the "CODE" field equal to 5000002800000, i.e. it is also in this area. What fields should be used to search for a connection so that Moscow ends up in the Moscow Region?

Answer 1

In 1931, a significant event took place in the history of the Moscow region - by decision of the Politburo, the city of Moscow was separated into an independent administrative and economic unit.