Recently I am making a small system in which I've 3 packages using Ms Access as database
1)Classes----> Based on OOP concepts
2)GUI------> The Jform + .java files
3)Images---->Just some icons i made
I've made a DBConnection
class in the Classes package(using UCanAccess
).
import java.sql.*;
public class DBConnection {
public DBConnection() {
try {
String driver = "net.ucanaccess.jdbc.UcanaccessDriver";
Class.forName(driver);
String dbPath = "jdbc:ucanaccess://E:\\University Docs\\BSCS 3A\\Object Oriented Programming\\LibraryManagementSystem\\LMSDatabase.accdb";
Connection con = DriverManager.getConnection(dbPath);
Statement st = con.createStatement();
System.out.println("Connection Succesful");
ResultSet rsObject = st.executeQuery(dbPath);
con.close();
} catch (Exception sqlEx) {
System.out.println(sqlEx);
}
} }
Next I've made a Loger
class for creating a login and logout methods in the same package.The problem is that how do I execute my query in this class by using the DBConnection
Class?This is the code for Loger
class
public class Loger {
private String lname, lpassword;
public Loger(String lname, String lpassword) {
this.lname = lname;
this.lpassword = lpassword;
//Login();
}
public String Login()throws ClassNotFoundException,SQLException
{
DBConnection d1 = new DBConnection();
String query1 = "SELECT * FROM Admintable WHERE Admin_ID = ' "+this.lname+" AND Admin_Password = '"+this.lpassword+"'" ;
return "Success!";
} }
In short I am stuck please help because I have to make more classes (OOP
based)and just make methods in such classes to execute different queries.
You need mysql-connector-java API which is to be imported in your project through project properties -> Libraries -> add jar.
Follow the sample code:
public class Database {
Connection conObj;
Statement stObj;
public Database() throws SQLException , ClassNotFoundException {
Class.forName("com.mysql.jdbc.Driver"); /*Loading Driver class for JDBC*/
conObj = DriverManager.getConnection("jdbc:mysql://localhost:3306/mytestdb","root",""); /*Creating Connection class's Object which consist of database url , username and password*/
stObj = conObj.createStatement();/*Creating Statement Class's object which is responsible for performing all db tasks*/
}
public void fetchData() throws Exception
{
String query = "select * from user";
ResultSet rs = stObj.executeQuery(query);
while(rs.next())
{
System.out.println("Name : "+rs.getString("name"));
System.out.println("age : "+rs.getInt("age"));
}
}
public void insertData(String name, int age) throws SQLException
{
if(name!=null && age!=0)
{
String query = "insert into user values(\""+name+"\","+age+")";
int a = stObj.executeUpdate(query);
if(a == 1)
{
System.out.println("Update Successful");
}
else
{
System.out.println("Update Failed");
}
}
}
void deleteData() {
}
void deleteData(String name) throws Exception
{
String query = "delete from user where name = \""+name+"\"";
int a = stObj.executeUpdate(query);
if(a == 1)
{
System.out.println("delete Successful");
}
else
{
System.out.println("deletion Failed");
}
}
}
public class main {
public static Database d;
public static Scanner sc;
static
{
try{
sc = new Scanner(System.in);
d = new Database();
}
catch(Exception e)
{
throw new RuntimeException(e);
}
}
public static void main(String... q)
{
main mn = new main();
try{
System.out.println("Enter your option");
System.out.println("1) fetch data");
System.out.println("2) insert data");
System.out.println("3) delete data");
System.out.println("\n /////////////////////////// \n");
int a = sc.nextInt();
switch(a)
{
case 1 :
mn.fetchData();
break;
case 2 :
mn.takeDetails();
break;
case 3 :
mn.deleteData();
break;
default:
System.out.println("Try Again");
break;
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
public void takeDetails() throws Exception
{
System.out.println("Enter name");
String name = sc.next();
System.out.println("Enter age");
int age = sc.nextInt();
d.insertData(name, age);
}
public void fetchData() throws Exception
{
d.fetchData();
}
private void deleteData() throws Exception {
System.out.println("Enter name of the user whose record is to be deleted");
String name = sc.next();
d.deleteData(name);
}
}
Read the comments written in between for explanation.For Complete tutorial follow the link Hope this helps.