text: alter table o_ex_task add column e_scheduled datetime;
  alter table o_ex_task add column e_ressubpath varchar(2048);
  alter table o_ex_task add column e_status_before_edit varchar(16);
  alter table o_ex_task add column fk_resource_id bigint;
  alter table o_ex_task add column fk_identity_id bigint;
  
  alter table o_ex_task add constraint idx_ex_task_ident_id foreign key (fk_identity_id) references o_bs_identity(id);
  alter table o_ex_task add constraint idx_ex_task_rsrc_id foreign key (fk_resource_id) references o_olatresource(resource_id);
  
  create table o_ex_task_modifier (
     id bigint not null,
     creationdate datetime not null,
     fk_task_id bigint not null,
     fk_identity_id bigint not null,
     primary key (id)
  );
  alter table o_ex_task_modifier ENGINE = InnoDB;
  
  alter table o_ex_task_modifier add constraint idx_ex_task_mod_ident_id foreign key (fk_identity_id) references o_bs_identity(id);
  alter table o_ex_task_modifier add constraint idx_ex_task_mod_task_id foreign key (fk_task_id) references o_ex_task(id);
  