alter table cr_revisions drop constraint cr_revisions_lob_fk; alter table cr_revisions add constraint cr_revisions_lob_fk foreign key (lob) references lobs on delete set null;
alter table cr_revisions drop constraint cr_revisions_lob_fk; alter table cr_revisions add constraint cr_revisions_lob_fk foreign key (lob) references lobs on delete set null;