STEP 3 (SQLConnection Class)

This simple application is meant to connect to MSSQL server as an EXTRA learning topic in this tutorial. To do this, we will make a new Class. Remember this is Java... everything in Java is a class.

For our SQLConnection class I suggest this simple code. You are free to create a better class, but for this tutorial matter, this is just perfect. So we create a new package in the "src" folder and name it "connections" and inside that package we create a new class named�"SQLConnection". And we copy this code:

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package connection;
import java.sql.*;
public class SQLConnection {
protected Connection con = null;
protected ResultSet rs = null;
public SQLConnection(String address, String db, String user, String pass)
{
try
{
String conString = "jdbc:sqlserver://"+address+";databaseName="+db;
con = DriverManager.getConnection(conString,user,pass);
}catch(SQLException sqlError){
//ERROR MANAGEMENT HERE
}
}
public boolean execQuery(String sql)
{
boolean result = false;
try
{
Statement stmt = con.createStatement();
stmt.execute(sql);
result = true;
}catch(SQLException sqlError){
//ERROR MANAGEMENT HERE
result = false;
}
return result;
}
public void execSelectQuery(String sql)
{
try
{
Statement stmt = con.createStatement();
this.rs = stmt.executeQuery(sql);
}catch(SQLException sqlError){
//ERROR MANAGEMENT HERE
}
}
public void disconnect()
{
try
{
con.close();
}catch(SQLException sqlError){
//ERROR MANAGEMENT HERE
}
}
}

STEP 4 (Item Class)

Now that we have our own database layer we can create a model for our items. This model will let us add items and show the lastest 5 from the database. Heres the simple class I made for this tutorial. You can upgrade it if you like.

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package models;
import java.sql.SQLException;
import connection.SQLConnection;
public class Item extends SQLConnection{
public Item() {
super("localhost", "todoList", "sqluser", "sqlpass");
}
public String[] lastItems(){
String[] result = new String[5];
this.execSelectQuery("SELECT TOP 5 * FROM items ORDER BY id DESC ");
int i=0;
try
{
while (this.rs.next())
{
result[i] = rs.getString("itemDescription");
i++;
}
}catch(SQLException sqlError)
{
//ERROR MANAGEMENT HERE
}
return result;
}
public boolean insert(String todo)
{
String sql = "INSERT INTO items (itemDescription) VALUES ('"+todo+"')";
return this.execQuery(sql);
}
}