如果作者不存在，java将其插入表中，但始终返回其ID

Question

我试图让这个函数只在数据库中不存在作者时插入作者

如果作者已经在“authors”表中（意思是相同的名字和姓氏），那么我希望此函数不插入作者，但我仍然希望它返回作者的ID，我不确定如何执行此操作

下面是我的insertAuthor函数，它可以插入作者，即使他已经存在：

public static int insertAuthor(Connection conn, Author author) throws SQLException
{
    ResultSet keys = null;
    int authorId;

    // Insert the new Authors into the authors table
    String sqlInsertAuthor = "INSERT into authors"
            + "(author_firstname, author_lastname)"
            + " VALUES (?, ?)";

    try (PreparedStatement statement = conn.prepareStatement(sqlInsertAuthor, Statement.RETURN_GENERATED_KEYS);)
    {
        statement.setString(1, author.getFirstName());
        statement.setString(2, author.getLastName());

        // Execute and return number of rows affected
        int affectedRows = statement.executeUpdate();

        // The number of affected rows should be equal to 1
        if (affectedRows == 1)
        {
            keys = statement.getGeneratedKeys();
            keys.next();
            authorId = keys.getInt(1);
        }
        else
        {
            return 0;
        }
    }
    catch (SQLException e)
    {
        System.err.println("ERROR INSERTING AUTHOR: " + e.getMessage());
        return 0;
    }

    return authorId;
}