-create table description_history(description varchar not null primary key, keep boolean, description_upper varchar);
-create table profiles(uuid varchar not null primary key, name not null, url not null, use_authentication boolean not null, auth_user varchar, auth_password varchar, order_no integer, permit_posting boolean default 0, theme integer default -1, preferred_accounts_filter varchar, future_dates integer, api_version integer, show_commodity_by_default boolean default 0, default_commodity varchar, show_comments_by_default boolean default 1);
-create table transactions(profile varchar not null, id integer not null, data_hash varchar not null, year integer not null, month integer not null, day integer not null, description varchar not null, comment varchar, keep boolean not null default 0);
+create table description_history(description varchar not null primary key, description_upper varchar, generation integer default 0);
+create unique index un_description_history on description_history(description_upper);
+create table transactions(profile varchar not null, id integer not null, data_hash varchar not null, year integer not null, month integer not null, day integer not null, description varchar not null, comment varchar, generation integer default 0);