Reading data from file and adding it to database without adding the same values

Question

So I have this program that reads the text file and add its content to my database. I have no problem here. But when new content is added to file and the program is run again, all the values are stored in the database from the beginning, but i just want the new content to be added on top when i run the program for the second time. How can I do this, here is my code. Thanks in advance!!

        public static void main(String[] args) throws IOException, SQLException {

    PreparedStatement preparedstatement = null;


    try{
        String read=null;
        in = new BufferedReader(new FileReader("patientlist.txt")); 
        while ((read = in.readLine()) != null) {
            String[] splited = read.split("\\s+");
            name=splited[0];
            age=splited[1];
            height=splited[2];
            weight=splited[3];      
            addpatient(connection, preparedstatement, name, age, height, weight);
        }

    }
    catch (IOException e) {System.out.println("There was a problem: " + e);}
        if (connection != null)
        try{connection.close();} catch(SQLException ignore){} 
    }


    public static void addpatient(Connection connection, PreparedStatement preparedstatement, String name, String age, String height, String weight) throws SQLException{
    preparedstatement=connection.prepareStatement("insert into allpatients(name, age, height, weight) values(?,?,?,?)");
    preparedstatement.setString(1, name);
    preparedstatement.setString(2, age);
    preparedstatement.setString(3, height);
    preparedstatement.setString(4, weight);
    preparedstatement.executeUpdate();


    }

How about querying the database to check if the record already exists before you insert it? — Qwerky
– Qwerky, Commented Sep 12, 2013 at 13:34
So your challenge is to detect the existence of previously inserted records? This isn't a Java question. It's pure SQL, really. Your answer will look something like "if not exists (select 1 from allpatients where ....) insert into allpatients values(...)". — CPerkins
– CPerkins, Commented Sep 12, 2013 at 13:36
Is there a UNIQE key? Is name unique? Can you empty your source file after added it in the database? Please consider to adjust indentation in your code to simplify readibility. — mauretto
– mauretto, Commented Sep 12, 2013 at 13:38
So i won't change my code but enter a statement in sql? I don't know what to write though.. — Solijoli
– Solijoli, Commented Sep 12, 2013 at 13:39

AppX · Accepted Answer · 2013-09-12 13:54:16Z

1

if (!isPatent(connection, preparedstatement, name)) 
    addpatient(connection, preparedstatement, name, age, height, weight);



    public static boolean isPatient(Connection connection,
            PreparedStatement preparedstatement, String name)
            throws SQLException {
        boolean exists = false;
        preparedstatement = connection
                .prepareStatement("select * from allpatients where name = ?");

        preparedstatement.setString(1, name);
        ResultSet rs = preparedstatement.executeQuery();
        if (rs.next()) {
            exists = true;
        }
        rs.close();
        return exists;
    }

answered Sep 12, 2013 at 13:54

AppX

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1 Comment

AppX Over a year ago

True mauretto. Think that it's the problem he wants to solve.

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