addMinionEx4

    public void addMinionEx4() throws IOException, SQLException {
        System.out.println("Enter minion info (copy the input):");
        String[] minionsInfo = reader.readLine().split("\\s+");
        String minionName = minionsInfo[1];
        int minionAge = Integer.parseInt(minionsInfo[2]);
        String townName = minionsInfo[3];

        System.out.println("Enter villain name:");
        String villainName = reader.readLine().split("\\s+")[1];

        int townId = getEntityIdByName(townName, "towns");

        if (townId < 0) {
            insertIntoTowns(townName);
            townId =  getEntityIdByName(townName, "towns");
            System.out.printf("Town %s was added to the database.%n", townName);
        }

        insertMinionIntoMinions(minionName, minionAge, townId);


        int villainId = getEntityIdByName(villainName, "villains");

        if (villainId < 0) {
            createVillain(villainName);
            villainId = getEntityIdByName(villainName, "villains");
            System.out.printf("Villain %s was added to the database.%n", villainName);
        }

        addMinionToVillain(minionName, villainId);

        System.out.printf("Successfully added %s to be minion of %s.%n", minionName, villainName);

    }

    private void addMinionToVillain(String minionName, int villainId) throws SQLException {
        int minionId = getEntityIdByName(minionName, "minions");
        String query = "INSERT INTO minions_villains VALUES (?, ?)";
        connection.setAutoCommit(false);
        PreparedStatement statement = connection.prepareStatement(query);
        statement.setInt(1, minionId);
        statement.setInt(2, villainId);
        statement.execute();
        connection.commit();
    }

    private void createVillain(String villainName) throws SQLException {
        String query = "INSERT INTO villains(name, evilness_factor) VALUES (?, ?)";
        connection.setAutoCommit(false);
        PreparedStatement statement = connection.prepareStatement(query);
        statement.setString(1, villainName);
        statement.setString(2, "evil");
        statement.execute();
        connection.commit();
    }

    private void insertMinionIntoMinions(String minionName, int minionAge, int townId) throws SQLException {
        String query = "INSERT INTO minions(name, age, town_id) VALUES (?, ?, ?)";
        connection.setAutoCommit(false);
        PreparedStatement statement = connection.prepareStatement(query);
        statement.setString(1, minionName);
        statement.setInt(2, minionAge);
        statement.setInt(3, townId);
        statement.execute();
        connection.commit();
    }

    private void insertIntoTowns(String townName) throws SQLException {
        String query = "INSERT INTO towns(name) VALUES (?)";
        connection.setAutoCommit(false);
        PreparedStatement statement = connection.prepareStatement(query);
        statement.setString(1, townName);
        statement.execute();
        connection.commit();
    }

    private int getEntityIdByName(String entityName, String tableName) throws SQLException {
        String query = String.format("SELECT id FROM %s WHERE name = ?", tableName);
        PreparedStatement statement = connection.prepareStatement(query);
        statement.setString(1, entityName);
        ResultSet resultSet = statement.executeQuery();

        return resultSet.next() ? resultSet.getInt(1) : -1;
    }