public List<String> getDistinctProducers(){
		Connection conn = null;
		PreparedStatement st = null;
		List<String> producers = new ArrayList<String>();
		try {
			conn = OracleDAOFactory.createConnection();
			st = conn.prepareStatement(GET_DISTINCT_PRODUCERS);
			ResultSet row = st.executeQuery();
			while(row.next()){
				producers.add(row.getString(PRODUCER));
			}
			return producers;
		} catch (SQLException e) {
			throw new ShopException("Can't get producers from database", e);
		} finally {
			try {
				if (st != null) {
					st.close();
				}
			} catch (SQLException e) {
				throw new ShopException(CANT_CLOSE_STATEMENT, e);
			}

			try {
				if (conn != null) {
					conn.close();
				}
			} catch (SQLException e) {
				throw new ShopException(CANT_CLOSE_CONNECTION, e);
			}

		}
	}