Update statement only runs once.?

So Im having an issue where the results of the first query are only getting updated once.

Statement statement = con1.createStatement();
    ResultSet qResult = statement.executeQuery("select e.Grade, e.StudentID, s.StudentID, s.Classification, s.CreditHours, s.GPA"+ " " +
                            "from Enrollment e, Student s" + " " +
                            "where e.StudentID = s.StudentID");

    double grade = 0.00;
    int tCredits = 0;
    float newGpa = 0;
    String nClass = "";
    PreparedStatement statement2;
    int rowCount = 0;
    String sId = "";
    //loop results
    while(qResult.next())
    {
        sId = qResult.getString(2);
        //1 parse grade - convert to double and save to variable
        grade = parseGrade(qResult.getString(1));
        //2 save Tcredit hours to var
        tCredits = qResult.getInt(5);
        //3 calc new GPA = ((gpa * tCred)+ (3 * grade))/(tCred +3)
        newGpa = (float) (((qResult.getDouble(6) * tCredits) + (3 * grade))/(tCredits + 3));
        //4 add 3 to Tcredit hours
        tCredits = tCredits + 3;
        //5 check tCredit hours and update classification
        nClass = getNewClass(tCredits);

        开发者_如何学Python//6 Update Tables!!
        statement = con1.createStatement();
        rowCount += statement.executeUpdate("update Student" + " " +
                              "set Classification=" + "'" + nClass + "'" + ", GPA=" + newGpa +", CreditHours=" + tCredits  + " " +
                              "where StudentID=" + qResult.getString(2));

    }
    System.out.println("rows Changed:::: " + rowCount);
    //statement.close();

}

I am trying to update each result as I traverse the results from my select query. I ahve check and there are multiple students enrolled in multiple classes so students do get returned more than once.

however the credits only get updated 1( +3) for every student that is in the enrollment table.

Please help, thanks!

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You have to use Updatable ResultSet.

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The issue is that JDBC does not allow table queires from multiple tables while attempting to make changes to those tables, concurrently.