Determining primary key columns in PGAdmin, if the constraint name is generated by system
I'm not sure I understood what you're asking, but if your question is how to determine what columns constitute a table's primary key you can query the catalog like so:
select c.conname constraint_name, o.relname table_name, a.attname column_name
from pg_constraint c 
inner join pg_class o
   on c.conrelid = o.oid
inner join pg_attribute a 
  on c.conrelid = a.attrelid 
-- pg_constraint.conkey is an array of pg_attribute.attnum values
-- &quot;with ordinality&quot; clause helps keep proper column ordering
inner join lateral unnest (c.conkey) with ordinality as cols (attnum, pos)
  on a.attnum = cols.attnum
where c.contype = 'p' 
order by conname, relname, pos