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Thread: Beginner Needs Help Inserting row to table

  1. #1
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    Default Beginner Needs Help Inserting row to table

    This is for a class assignment. I have to create a student class with three sub-classes(grad, undergrad, part-time). Within the student class I need to use set and get methods() to capture the data. The student object is then stored in the database. I can access the database. I was able to insert a record @ the cmd prompt using mysql. I can query the database in java and produce a reseultSet. I am unable to add data to the database. I know my get/set methods create the desired student object because I overrode the toString() method and was able to print the object info that was input at the prompts. Any help is greatly apprieciated.

    Thanks,
    Moni
    Student Class
    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
    package registrar;
    import java.sql.*;
    import java.util.Scanner;
    /**
     *
     * @author Moni
     */
    public abstract class Student
    {
        private String firstName;
        private String lastName;
        private int studentID;
        private double gradeAverage;
        String status;
        private String mentorName;
        private String level;
        private String thesisTitle;
        private String thesisAdvisor;
        private String company;
     
        //overloaded constructors
        public Student()
        {
     
        }
        public Student(String first, String last, int id, double gpa,
                String stat, String mentor)
        {
            firstName = first;
            lastName = last;
            studentID = id;
            gradeAverage = gpa;
            status = stat;
            mentorName = mentor;
        }
        public Student(String first, String last, int id, double gpa,
                String stat, String mentor, String lvl, String title,
                String advisor, String comp)
        {
            firstName = first;
            lastName = last;
            studentID = id;
            gradeAverage = gpa;
            status = stat;
            mentorName = mentor;
            level = lvl;
            thesisTitle = title;
            thesisAdvisor = advisor;
            company = comp;
        }
        //getters and setters
        public String getFirstName()
        {
            return firstName;
        }
        public String getLastName()
        {
            return lastName;
        }
        public void setFirstName(String first)
        {
     
            firstName = first;
     
        }
        public void setLastName(String last)
        {
            lastName = last;
        }
        public int getStudentID()
        {
            return studentID;
        }
        public void setStudentID(int id)
        {
            studentID = id;
        }
        public String getStatus()
        {
            return status;
        }
        public void setStatus(String s)
        {
            status = s;
        }
        public double getGPA()
        {
            return gradeAverage;
        }
        public void setGPA(double gpa)
        {
            gradeAverage = gpa;
        }
        public String getMentor()
        {
            return mentorName;
        }
        public void setMentor(String mentor)
        {
            mentorName = mentor;
        }
        public String getLevel()
        {
            return level;
        }
        public void setLevel(String lvl)
        {
            level = lvl;
        }
        public String getTitle()
        {
            return thesisTitle;
        }
        public void setTitle(String title)
        {
            thesisTitle = title;
        }
        public String getAdvisor()
        {
            return thesisAdvisor;
        }
        public void setAdvisor(String advisor)
        {
            thesisAdvisor = advisor;
        }
        public String getCompany()
        {
            return company;
        }
        public void setCompany(String comp)
        {
            company = comp;
        }
        //toString override
        @Override
        public String toString()
        {
            return "student[Registration= " + studentID
                    + firstName + "\t"
                    + lastName + "\t"
                    + gradeAverage + "\t"
                    + status + "\t"
                    + mentorName + "\t"
                    + level + "\t"
                    + thesisTitle + "\t"
                    + thesisAdvisor + "\t"
                    + company + "]";
        }
        //abstract methods
        public abstract double calculateTuition();
     
        public abstract String add();
     
        public abstract boolean update();
     
        public abstract boolean delete();
     
     
     
        public static ResultSet getQuery() throws SQLException
        {
            Statement stmt = null;
            Connection conn = SimpleDataSource.getConnection();
            try
            {
                stmt = conn.createStatement(
                        ResultSet.TYPE_SCROLL_SENSITIVE,
                        ResultSet.CONCUR_UPDATABLE);
                String select = "SELECT * from student";
                ResultSet rs = stmt.executeQuery(select);
                System.out.println("Student Records:");
                while(rs.next())
                {
                    System.out.println("Student ID#:\t" + rs.getString("studentID"));
                    System.out.println("First Name:\t" + rs.getString("firstName"));
                    System.out.println("Last Name:\t" + rs.getString("lastName"));
                    System.out.println("Grade Avg:\t" + rs.getString("gpa"));
                    System.out.println("Status:\t" + rs.getString("status"));
                    System.out.println("Mentor:\t" + rs.getString("mentor"));
                    System.out.println("Level:\t" + rs.getString("level"));
                    System.out.println("Title:\t" + rs.getString("thesisTitle"));
                    System.out.println("Advisor:\t" + rs.getString("thesisAdvisor"));
                    System.out.println("Company:\t" + rs.getString("company"));
                }
                stmt.close();
                conn.close();
            }
            catch (SQLException e)
            {
                System.out.println(e.getMessage());
            }
            return null;
        }
     
     
    }
    Graduate sub-class
    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
    package registrar;
    import java.io.File;
    import java.io.IOException;
    import java.sql.*;
    import java.util.ArrayList;
    import java.util.Scanner;
    /**
     *
     * @author Moni
     */
    public class Graduate extends Student
    {
        double rate;
        double creditHours = 16;
        public void setGradRate(double rate)
        {
            if (status.equalsIgnoreCase("non-resident"))
            {
                rate = 350;
            }
            else
            {
                rate = 300;
            }
        }
        @Override
        public double calculateTuition()
        {
            this.setGradRate(rate);
            double tution = rate * creditHours;
            return tution;
        }
     
        @Override
        public String add()
        {
            Connection conn = null;
            Statement stmt1 = null;
            try
            {
               Scanner in = new Scanner(System.in);
     
               conn = SimpleDataSource.getConnection();
               stmt1 = conn.createStatement();
     
               System.out.print("Enter the Student ID #: ");
               int id = in.nextInt();
               System.out.print("Enter First Name: ");
               String first = in.next();
               System.out.print("Enter Last Name: ");
               String last = in.next();
               System.out.print("Enter Student Status: ");
               String stat = in.next();
               System.out.print("Enter Mentor's Name: ");
               String mentor = in.next();
               double gpa = 3.5;
               System.out.print("Enter the Student's Level: ");
               String lvl = in.next();
               System.out.print("Enter the Thesis Title: ");
               String title = in.next();
               System.out.print("Enter the Thesis Advisor's Name: ");
               String advisor = in.next();
               System.out.print("Enter the Company's Name: ");
               String comp = in.next();
               //set variables
               this.setStudentID(id);
               this.setFirstName(first);
               this.setLastName(last);
               this.setGPA(gpa);
               this.setStatus(stat);
               this.setMentor(mentor);
               this.setLevel(lvl);
               this.setTitle(title);
               this.setAdvisor(advisor);
               this.setCompany(comp);
     
               stmt1.execute("INSERT into student"
                       + "(studentID, firstName, lastName, gpa, status, mentor,"
                       + "level, thesisTitle, thesisAdvisor, company)"
                       + "VALUES ('"
                       + getStudentID() + "','"
                       + getFirstName() + "','"
                       + getLastName() + "','"
                       + getGPA() + "','"
                       + getStatus() + "','"
                       + getMentor() + "','"
                       + getLevel() + "',"
                       + getTitle() + "','"
                       + getAdvisor() + "','"
                       + getCompany() + "')");
              // try
              // {
             //      stmt1.execute(addStudent);
                   //System.out.println("1 record added");
     
              // }
              // catch(SQLException s)
              // {
               //    
              //     System.exit(0);
              // }
               stmt1.close();
               conn.close();
            }
            catch(Exception e)
            {
                System.out.println("SQL statement is not executed!");
            }
            return null;
     
        }
     
        @Override
        public boolean update() {
            throw new UnsupportedOperationException("Not supported yet.");
        }
     
        @Override
        public boolean delete() {
            throw new UnsupportedOperationException("Not supported yet.");
        }
     
    }
    Registration (main)
    /*
     * This is the main program that manipulates and queries the student
     * database table.
     * APA References:
     * [url=http://download.oracle.com/javase/tutorial/jdbc/basics/prepared.html]Using Prepared Statements (The Java™ Tutorials > JDBC(TM) Database Access > JDBC Basics)[/url]
     * retrieved March 5, 2011a
     *
     */
     
    package registrar;
    import java.io.File;
    import java.io.IOException;
    import java.sql.*;
    import java.util.Scanner;
    /**
     *
     * @author Moni
     */
    public class Registration
    {
     
        /**
         * Finds and returns a list of students registered
         */
        public static void main (String[] args) throws
                IOException, SQLException, ClassNotFoundException
        {
            //SimpleDataSource.init(args[0]);
     
            Scanner in = new Scanner(System.in);
     
            System.out.print("Welcome To Student Records. Select Action:"
                    + "[A]ADD, [D]DELETE, [E]EDIT: ");
            String action = in.next();
     
            if(action.equalsIgnoreCase("A"))
            {
     
               System.out.print("Enter Student Type: "
                       + "[G]Grad/[P]Part-time/[U]Undergrad: ");
               String type = in.next();
               //create graduate object to add
               if(type.equalsIgnoreCase("g"))
               {
                   Graduate grad = new Graduate();
     
                   // add to the database
                   grad.add();
                   //String gradString = grad.toString();
                   //System.out.println(gradString);
                   //System.out.println(grad.getFirstName());
     
               }
               //create undergrad object to add
               else if(type.equalsIgnoreCase("u"))
               {
     
               }
            }
     
     
            ResultSet query = Student.getQuery();
            System.out.print(query);
     
        }
     
     
     
    }
    Last edited by copeg; March 9th, 2011 at 08:17 PM.


  2. #2
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    Default Re: Beginner Needs Help Inserting row to table

    For future reference, please see the following link for how to correctly use the highlight/code tags (I've edited your post for you) Announcements - What's Wrong With My Code?

    What exactly is the problem? You mention not being able to insert using jdbc, but does the statement execute and/or are there exceptions thrown?

  3. #3
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    Default Re: Beginner Needs Help Inserting row to table

    Thanks for editing my post correctly. I am thorowing my sql exception in the add() method (located in the Graduate sub-class), it is catching exception e "SQL Statement not executed!". I am unsure if I am unable to add new data to the table because my java code/syntax for inserting into the table is incorrect. The assignment states that I have to use the get/set methods to store the variable information of my student object. I thought I was correctly calling back that information (in the grad-subclass) "stmt1.execute(INSERT into student ......)". Will the mysql language not allow me to call my get*() methods instead of using variables?

  4. #4
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    Default Re: Beginner Needs Help Inserting row to table

    Rather than printing out a custom statement when an exception is thrown, call printStackTrace() on the Exception object - this is MUCH more informative and typically will give a detailed description of the error. Recommend seeing what that prints out and posting it here.

  5. #5
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    Default Re: Beginner Needs Help Inserting row to table

    [ERROR]com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorEx ception: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '','Theory','none')' at line 1
    at sun.reflect.NativeConstructorAccessorImpl.newInsta nce0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInsta nce(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newI nstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Construc tor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:40 6)
    at com.mysql.jdbc.Util.getInstance(Util.java:381)
    at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:1030)
    at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:956)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.ja va:3491)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.ja va:3423)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:19 36)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java :2060)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionIm pl.java:2536)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionIm pl.java:2465)
    at com.mysql.jdbc.StatementImpl.execute(StatementImpl .java:734)
    at registrar.Graduate.add(Graduate.java:79)
    at registrar.Registration.main(Registration.java:48)[/ERROR]

    line 79 is the stmt1.execute(....insert into db table...)
    line 48 calls the method that holds the stmt1.execute code.
    My question is this: is MySQL not able to get the variable values from my get*() methods?

  6. #6
    Administrator copeg's Avatar
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    Default Re: Beginner Needs Help Inserting row to table

    My question is this: is MySQL not able to get the variable values from my get*() methods?
    No....SQL has nothing to do with those gets (that all happens on the java side). The exception is fairly descriptive: your SQL syntax is incorrect. My advice to debug is to first create a string that represents your query, then print that query out using System.out.println to see what it actually looks like - there is a syntax error that is not evident from the code itself and printing it out will allow you to see the query (and even test it directly with MySQL)

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