--From PVD for conversion
-- Add/modify columns 
alter table I_CUSTOMERACTIVITIES add INVOICEFREQUENCY number default 0 not null;
-- Create/Recreate primary, unique and foreign key constraints 
alter table I_CUSTOMERACTIVITIES
  add constraint FK_I_CUSTOMERACT_INVFREQ foreign key (INVOICEFREQUENCY)
  references invoicefrequency (INVOICEFREQUENCY_ID);