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- package hu.ttk.data;
- import hu.ttk.data.entity.Student;
- import java.sql.DriverManager;
- import java.sql.ResultSet;
- import java.sql.Statement;
- import java.util.ArrayList;
- //Adatbázishoz csatlakozás.
- public class DatabaseDAO implements DataProvider{
- private java.sql.Connection conn;
- private void initConnection() throws Exception{
- if(conn==null || conn.isClosed()){
- //driver betöltése.
- Class.forName("com.mysql.jdbc.Driver");
- //connection string
- String url = "jdbc:mysql://iroda.lanoga.eu:3307/test";
- conn = DriverManager.getConnection(url,"test","lanogapass");
- }
- }
- @Override
- public ArrayList selectAll() throws Exception {
- initConnection();
- ArrayList back = new ArrayList();
- //Egyszerű sql utasítások.
- Statement st = conn.createStatement();
- //Gyűjtemény, amiben a tábla összes eleme benne van.
- ResultSet rs = st.executeQuery("select * from student");
- while(rs.next()){
- //Adatbázis oszlopai.
- int id = rs.getInt("id");
- String name = rs.getString("name");
- String faculty = rs.getString("faculty");
- int age = rs.getInt("age");
- //Primitív tipus létrehozása. ""+id
- Student stu = new Student(""+id, name, faculty,""+age);
- back.add(stu);
- }
- rs=null;//Memória optimalizáslása.
- st.close();
- conn.close();
- return back;
- }
- //Beszúrás az adatbázisba.
- public void insert(Student stu) throws Exception {
- initConnection();
- Statement st= conn.createStatement();
- String sql = "insert into student (name,faculty,age)"
- + " values(\""+stu.getName()+"\",\""+stu.getFaculty()+"\","+stu.getAge()+")";
- System.out.println("sql"+sql);
- st.execute(sql);
- st.close();
- conn.close();
- }
- //Módosítás az adatbázisban.
- public void update(Student stu) throws Exception {
- initConnection();
- Statement st= conn.createStatement();
- String sql = "update student set name=\""+stu.getName()+"\","
- + "faculty=\""+stu.getFaculty()+"\","+"age="+stu.getAge()
- +" where id="+stu.getId();
- System.out.println("sql"+sql);
- st.executeUpdate(sql);
- st.close();
- conn.close();
- }
- //Törlés az adatbázisban.
- public void delete(Student stu) throws Exception {
- initConnection();
- Statement st= conn.createStatement();
- String sql="delete from student where id="+stu.getId();
- System.out.println("sql"+sql);
- st.execute(sql);
- st.close();
- conn.close();
- }
- }
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