unable to set repeating attributes for dm_extern_file table

Running this DQL throws an error but unable to find a solution
update dm_extern_file object
set a_plugin_id = '6701d72080000d01'
set a_location = 'storage_02'
set a_config_name = 'bciDevBase'
set a_platform = 1
where name = 'test_04'

The a_plugin_id, a_location, a_config_name, and a_platform will cause the error on both the create dm_extern_file object and update statements.

I have tried it as

update dm_extern_file object
set a_plugin_id [0]= '6701d72080000d01'
set a_location [0]= 'storage_02'
set a_config_name [0] = 'bciDevBase'
set a_platform [0]= 1
where name = 'test_04'

but nothing works. The error produced is
[DM_QUERY_F_UP_SAVE]fatal: "UPDATE: An error has occurred during a save operation"

Any suggestions?