diff --git a/schema/changes02.sql b/schema/changes02.sql
new file mode 100644
index 0000000..64647ff
--- /dev/null
+++ b/schema/changes02.sql
@@ -0,0 +1,106 @@
+CREATE TABLE account_entry_reference_t (
+    id serial not null primary key,
+    account integer     not null   references account_t (id),
+    account_entry integer not null references account_entry_t (id)
+);
+
+
+CREATE OR REPLACE VIEW joined_account_entry_t AS
+  SELECT ae.id as id, 
+         ae.description as description, 
+         ae.account as account, 
+         ae.created_at as created_at, 
+         ae.amount as amount, 
+         ae.account_entry_category as account_entry_category, 
+         ae.document_no as document_no, 
+         ae.fiscal_year as fiscal_year,
+         false as is_reference, 
+         0 as base_account
+    FROM account_entry_t ae
+  UNION
+  SELECT ae.id as id, 
+         ae.description as description, 
+         aer.account as account, 
+         ae.created_at as created_at, 
+         ae.amount as amount, 
+         ae.account_entry_category as account_entry_category, 
+         ae.document_no as document_no, 
+         ae.fiscal_year as fiscal_year,
+         true as is_reference, 
+         ae.account as base_account
+    FROM account_entry_t ae,
+         account_entry_reference_t aer
+    WHERE ae.id = aer.account_entry;
+
+update account_t set description = 'fallback_account' where id = 33;
+delete from account_t where id = 32;
+
+insert into account_t (id, description) values (1000, 'ledger');
+
+update account_entry_t set amount = amount * -1.0 where account=33;
+update account_entry_t set amount = amount * -1.0 where account in (34,35,36,37);
+
+
+DO $$
+DECLARE
+  entry_id integer;
+BEGIN
+  RAISE NOTICE 'Start migration';
+
+  FOR entry_id IN
+    SELECT id
+      FROM account_entry_t
+      WHERE account IN (33,34,35,36,37)
+  LOOP
+    RAISE NOTICE 'About to migrate entry %', entry_id;
+    INSERT INTO account_entry_reference_t (account, account_entry) VALUES (1000, entry_id);
+  END LOOP;
+END;
+$$;
+
+update account_entry_t 
+  set description = 'Miete ' || extract(year from created_at)::text || ' ' || to_char(to_date(extract(month from created_at)::text, 'MM'), 'Month') 
+  where account_entry_category = 2 and description = 'Miete';
+
+
+DO $$
+DECLARE
+  entry RECORD;
+  tenant RECORD;
+BEGIN
+  RAISE NOTICE 'Start migration of tenant accounts';
+
+  FOR entry IN
+    SELECT id, description, account
+      FROM account_entry_t
+      WHERE account_entry_category = 2
+  LOOP
+    RAISE NOTICE 'About to migrate entry %', entry.id;
+    INSERT INTO account_entry_reference_t (account, account_entry) VALUES (1000, entry.id);
+    SELECT * 
+      INTO tenant
+      FROM tenant_t
+      WHERE account = entry.account;
+    RAISE NOTICE 'Tenant: % %', tenant.firstname, tenant.lastname;
+    UPDATE account_entry_t
+      SET description = description || ' ' || tenant.firstname || ' ' || tenant.lastname
+      WHERE id = entry.id;
+  END LOOP;
+END;
+$$;
+
+CREATE OR REPLACE FUNCTION maintain_ledger()
+RETURNS TRIGGER
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  INSERT INTO account_entry_reference_t (account, account_entry) VALUES (1000, NEW.id);
+  RETURN NEW;
+END;
+$$;
+
+CREATE TRIGGER maintain_ledger_trigger
+  AFTER INSERT ON account_entry_t
+  FOR EACH ROW
+  WHEN (NEW.account != 1000 AND NEW.account_entry_category NOT IN (3, 4))
+  EXECUTE FUNCTION maintain_ledger();