A - Errors

command line error

db2 delete from schemax.tablea where id=127

Output:

DB21034E The command was processed as an SQL statement because it was not a valid Command Line Processor command. During SQL processing it returned: SQL0440N No authorized routine named "=" of type "FUNCTION" having compatible arguments was found. SQLSTATE=42884

B - CAUSES

Which indicates that the problem is a referential constraint corruption

C - RESOLVING

Get all constraints names: (check constraint, primary keys, foreign key, etc)

db2look -d <dbname> -e -x  -t <tabname>

Drop all constraints

db2 alter table <table_name> drop constraint <constraint_name>

Recreate them, and try to delete your data again