trigger question.

Hi.
Has anyone migrated from Oracle to Postgresql there ?

I have a problem with trigger. I don't find a way to disable it.
Oracle statement :
ALTER TRIGGER "TRG_DT_ACTI"  ENABLE
or
ALTER TRIGGER "TRG_DT_ACTI"  DISABLE
I am looking for a way to do the same thing with postgresql.

I want to disable trigger before COPY and enable it after.
How can I do that?

Thank you for your help.

Regards,
Alain.