You are not permitted to delete primary key columns or
columns in system tables.
About this task
Attention: Dropping a column requires a considerable
amount of preliminary action to identify and remove any external dependencies
on the column. This involves searching for any references to the column
within triggers, procedures, views, restriction filters, probes rules
files, and gateway mapping files. Be aware also that if you drop a
column that has triggers, procedures, views, or restriction filters
that depend on it, these dependent objects are also deleted, with
a warning being written to the ObjectServer log file.
To
delete a table column after confirming that no external dependencies
exist: