While I am trying to resolve -668 error for DB2, the solution is to set integrity on the related tables.
However, I ended up trying to set integrity on a set of tables with cyclical dependencies. So the command
SET INTEGRITY for <table> immediate checked
does not work.
Searching more, I found that the solution is actually the same command, but all the dependent table should be comma separated. Something like the below.
SET INTEGRITY for table_a, table_b, table_c immediate checked
Hope this helps!