Using Java: Lastly add 2 functions to Update and Delete student information. Tes

Question

Using Java:

Lastly add 2 functions to Update and Delete student information.

Testing Code in Main() method à

Student s3 = new Student();

s3.selectDB(6);

s3.deleteDB();

And

Student s4 = new Student ();

s4.selectDB(7);

s4.setZipcode(30106);

s4.updateDB();

-------------------------------------------

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

import java.sql.Statement;

public class Student {

private int SID;

private String FirstName, LastName, Street, City, State;

private int Zip;

private String EMail;

private double GPA;

public Student() {

}

public Student(int SID, String firstName, String lastName, String street, String city, String state, int zip, String EMail, double GPA) {

this.SID = SID;

FirstName = firstName;

LastName = lastName;

Street = street;

City = city;

State = state;

Zip = zip;

this.EMail = EMail;

this.GPA = GPA;

}

public void display() {

System.out.println("ID: " + SID);

System.out.println("Name: " + FirstName + " " + LastName);

System.out.println("Street: " + Street);

System.out.println("City: " + City);

System.out.println("State: " + State);

System.out.println("Zip: " + Zip);

System.out.println("Email: " + EMail);

System.out.println("GPA: " + GPA);

}

public static void main(String[] args) {

Student s1 = new Student(4,"Frank", "Jones", "123 Main", "Atlanta", "GA", 30133, "fj@yahoo.com", 3.2);

s1.display();

}

public void insertDB(int SID, String FirstName, String LastName, String Street, String City, String State, int Zip, String EMail, double GPA){

// fillin the object

this.SID = SID;

this.FirstName = FirstName;

this.LastName = LastName ;

this.Street = Street;

this.City= City;

this.State = State;

this.Zip = Zip;

this.EMail = EMail;

this.GPA = GPA;

// forming the query with the given values

StringBuffer query = new StringBuffer("insert into student values(");

query.append(SID);

query.append(",");

query.append("'"+FirstName+"'");

query.append(",");

query.append("'"+LastName+"'");

query.append(",");

query.append("'"+Street+"'");

query.append(",");

query.append("'"+City+"'");

query.append(",");

query.append("'"+State+"'");

query.append(",");

query.append(Zip);

query.append(",");

query.append("'"+EMail+"'");

query.append(",");

query.append(GPA+")");

Connection con = null;

try {

// change the URL according to the connection

con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sonoo","user","password");

} catch (SQLException e) {

System.out.println("Problem in Connecting Db");

e.printStackTrace();

}

Statement st = null;

try {

st = con.createStatement();

} catch (SQLException e) {

System.out.println("Problem in creating statement");

e.printStackTrace();

}

try {

st.executeUpdate(new String(query));

} catch (SQLException e) {

System.out.println("Problem while inserting data");

e.printStackTrace();

}

}

}

Explanation / Answer

// PROGRAM FOR DELETING THE STUDENT RECORD

import java.util.ArrayList;

import java.util.List;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemSelectedListener;

import android.widget.Button;

import android.widget.Spinner;

import android.widget.TextView;

import android.widget.Toast;

public class Delete extends Activity {

Spinner s1;

Button deleteBtn;

String key;

public ArrayList<TagModel> _contact = new ArrayList<TagModel>();

DatabaseHandler db = new DatabaseHandler(this);

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.delete_tag);

// Initializations

s1 = (Spinner) findViewById(R.id.spinner1);

deleteBtn = (Button) findViewById(R.id.button1);

List<TagModel> obj = new ArrayList<TagModel>();

obj = db.getAllTags();

CustomAdapter adapter = new CustomAdapter(Delete.this, obj);

s1.setAdapter(adapter);

s1.setOnItemSelectedListener(new OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> parent, View view,

int position, long id) {

TextView keyview = (TextView) view.findViewById(R.id.textView1);

key = keyview.getText().toString();

}

@Override

public void onNothingSelected(AdapterView<?> parent) {

}

});

deleteBtn.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

db.deleteTag(key);

Toast.makeText(getApplicationContext(), "Record Deleted",

Toast.LENGTH_LONG).show();

db.close();

finish();

}

});

}

}

/// PROGRAM FOR UPDATING THE RECORD

import java.util.ArrayList;

import java.util.List;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemSelectedListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Spinner;

import android.widget.TextView;

import android.widget.Toast;

public class Update extends Activity {

Spinner s1;

Button updateBtn;

EditText edittext2,editText3,editText4,editText5;

String key, Name,Address,Course,Year;

public ArrayList<TagModel> _contact = new ArrayList<TagModel>();

DatabaseHandler db = new DatabaseHandler(this);

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.update_tag);

// Initializations

s1 = (Spinner) findViewById(R.id.spinner1);

edittext2 = (EditText) findViewById(R.id.editText2);

editText3 = (EditText) findViewById(R.id.editText3);

editText4 = (EditText) findViewById(R.id.editText4);

editText5 = (EditText) findViewById(R.id.editText5);

updateBtn = (Button) findViewById(R.id.button1);

List<TagModel> obj = new ArrayList<TagModel>();

obj = db.getAllTags();

CustomAdapter adapter = new CustomAdapter(Update.this, obj);

s1.setAdapter(adapter);

s1.setOnItemSelectedListener(new OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> parent, View view,

int position, long id) {

TextView keyview = (TextView) view.findViewById(R.id.textView1);

TextView tagview = (TextView) view.findViewById(R.id.textView2);

TextView addressview = (TextView) view.findViewById(R.id.textView3);

TextView courseview = (TextView) view.findViewById(R.id.textView4);

TextView yearview = (TextView) view.findViewById(R.id.textView5);

key = keyview.getText().toString();

Name = tagview.getText().toString();

Address = addressview.getText().toString();

Course = courseview.getText().toString();

Year = yearview.getText().toString();

edittext2.setText(Name);

editText3.setText(Address);

editText4.setText(Course);

editText5.setText(Year);

}

@Override

public void onNothingSelected(AdapterView<?> parent) {

}

});

updateBtn.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Name = edittext2.getText().toString();

Address = editText3.getText().toString();

Course = editText4.getText().toString();

Year = editText5.getText().toString();

db.updateTag(key, Name, Address, Course, Year);

Toast.makeText(getApplicationContext(), "Record Updated",

Toast.LENGTH_LONG).show();

db.close();

finish();

}

});

}

}

// DATABASE HANDLER OF ALL FUNCTION

import java.util.ArrayList;

import java.util.List;

import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHandler extends SQLiteOpenHelper {

// Version of database you are using

public static final int DATABASE_VERSION = 1;

// DatabaseName

public static final String DATABASE_NAME = "TagDB";

// Tag TableName

public static final String TABLE_TAG = "Tag";

// Tag Table ColumnName

public static final String KEY_ID_COLUMN = "key";

public static final String TAG_NAME_COLUMN = "tagname";

public static final String ADDRESS_COLUMN = "address";

public static final String COURSE_COLUMN = "course";

public static final String YEAR_COLUMN = "year";

  

// Creating Tables

public DatabaseHandler(Context context) {

super(context, DATABASE_NAME, null, DATABASE_VERSION);

}

@Override

public void onCreate(SQLiteDatabase db) {

String CREATE_TAG_TABLE = "CREATE TABLE " + TABLE_TAG + "("

+ KEY_ID_COLUMN + " INTEGER PRIMARY KEY," + TAG_NAME_COLUMN

+ " TEXT," + ADDRESS_COLUMN + "ADDRESS," + COURSE_COLUMN + "COURSE," + YEAR_COLUMN + "YEAR)";

db.execSQL(CREATE_TAG_TABLE);

}

// Upgrading database

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

// Drop older table if existed

db.execSQL("DROP TABLE IF EXISTS " + TABLE_TAG);

// Create tables again

onCreate(db);

}

// Adding new TAG

void addTag(TagModel obj) {

SQLiteDatabase db = this.getWritableDatabase();

ContentValues values = new ContentValues();

values.put(KEY_ID_COLUMN, obj.getKey());// Tag Key

values.put(TAG_NAME_COLUMN, obj.getTagName()); // Tag Name

values.put(ADDRESS_COLUMN, obj.getAddress());

values.put(COURSE_COLUMN, obj.getCourse());

values.put(YEAR_COLUMN, obj.getYear());

// Inserting Row

db.insert(TABLE_TAG, null, values);

// 2nd argument is String containing nullColumnHack

db.close(); // Closing database connection

}

// Getting single TAG

TagModel getTag(int key) {

SQLiteDatabase db = this.getReadableDatabase();

Cursor cursor = db.query(TABLE_TAG, new String[] { KEY_ID_COLUMN,

TAG_NAME_COLUMN , ADDRESS_COLUMN, COURSE_COLUMN, YEAR_COLUMN }, KEY_ID_COLUMN + "=?",

new String[] { String.valueOf(key) }, null, null, null, null);

if (cursor != null)

cursor.moveToFirst();

TagModel obj = new TagModel(Integer.parseInt(cursor.getString(0)),

cursor.getString(1),cursor.getString(2),cursor.getString(3),cursor.getString(4));

// return obj

return obj;

}

// Getting All Contacts

public List<TagModel> getAllTags() {

List<TagModel> tagList = new ArrayList<TagModel>();

// Select All Query

String selectQuery = "SELECT * FROM " + TABLE_TAG;

SQLiteDatabase db = this.getReadableDatabase();

Cursor cursor = db.rawQuery(selectQuery, null);

// looping through all rows and adding to list

if (cursor.moveToFirst()) {

do {

TagModel obj = new TagModel();

obj.setKey(Integer.parseInt(cursor.getString(0)));

obj.setTagName(cursor.getString(1));

// Adding obj to list

tagList.add(obj);

} while (cursor.moveToNext());

}

// return contact list

return tagList;

}

public void updateTag(String key, String name, String address,

String course, String year) {

// TODO Auto-generated method stub

}

public void deleteTag(String key) {

// TODO Auto-generated method stub

}

}

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