alter table lang_message_keys add 
          upgrade_status varchar2(30)
                         constraint lang_message_keys_us_ck
                         check (upgrade_status in ('no_upgrade', 'added','deleted'));

alter table lang_messages add
    upgrade_status     varchar2(30)
                       constraint lang_messages_us_ck
                       check (upgrade_status in ('no_upgrade', 'added', 'deleted', 'updated'));

create table lang_messages_audit (    
    message_key        varchar2(200)
                       constraint lang_messages_audit_key_nn
                       not null,
    package_key        varchar2(100)
                       constraint lang_messages_audit_p_key_nn
                       not null,
    locale             varchar2(30) 
                       constraint lang_messages_audit_l_fk
                       references ad_locales(locale)
                       constraint lang_messages_audit_l_nn
                       not null,
    message            clob,
    overwrite_date     date default sysdate not null,
    overwrite_user     integer
                       constraint lang_messages_audit_ou_fk
                       references users (user_id),
    constraint lang_messages_audit_fk
    foreign key (message_key, package_key) 
    references lang_message_keys(message_key, package_key)
    on delete cascade
);