DBF

package cas3;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBF {
    static PreparedStatement pst = null;

    public static boolean unesiNastavnika(Nastavnik n) {
        try {
            String unos = "INSERT INTO NASTAVNIK VALUES (?, ?, ?, ?)";
            pst = DBConnection.getConnection().prepareStatement(unos);
            pst.setInt(1, n.getNastavnik_id());
            pst.setString(2, n.getIme());
            pst.setString(3, n.getPrezime());
            pst.setString(4, n.getZvanje());
            pst.executeUpdate();

            return true;
        } catch(Exception e) {
            System.err.println(e.getMessage());

            return false;
        } finally {
            if (pst != null) {
                try {
                    pst.close();
                } catch (SQLException e) {
                    System.err.println(e.getMessage());
                }
            }
        }
    } // kraj unesiNastavnika

    @SuppressWarnings("finally")
    public static boolean obrisiNastavnika(int nastavnik_id) {
        boolean rez = false;
        String izPredaje = "DELETE FROM PREDAJE WHERE nastavnik_id= ?";
        String izNastavnik = "DELETE FROM NASTAVNIK WHERE nastavnik_id= ?";
        try {
            DBConnection.getConnection().setAutoCommit(false);

            pst = DBConnection.getConnection().prepareStatement(izPredaje);
            pst.setInt(1, nastavnik_id);
            pst.executeUpdate();

            pst = DBConnection.getConnection().prepareStatement(izNastavnik);
            pst.setInt(1, nastavnik_id);
            pst.executeUpdate();

            DBConnection.getConnection().commit();
            rez = true;
        } catch (Exception e) {
            System.err.println(e.getMessage());
            try {
                DBConnection.getConnection().rollback();
            } catch (SQLException e1) {
                System.err.println(e.getMessage());
            }
        } finally {
            if (pst != null) {
                try {
                    pst.close();
                } catch (SQLException e) {
                    System.err.println(e.getMessage());
                }
            }

            return rez;
        }
    }

    public static void prikaziPredmete(int nastavnik_id) {
        Statement stmt = null;
        ResultSet rez = null;
        String upit = "SELECT naziv FROM PREDMET WHERE predmet_id IN (SELECT predmet_id FROM PREDAJE WHERE nastavnik_id=" + nastavnik_id + ")";

        try {
            stmt = DBConnection.getConnection().createStatement();
            rez = stmt.executeQuery(upit);

            while (rez.next()) {
                System.out.println(rez.getString(1));
            }
        } catch (Exception e) {
            System.err.println(e.getMessage());
        } finally {
            if (rez != null) {
                try {
                    rez.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }

    }

    @SuppressWarnings("finally")
    public static boolean promjeniPrezime(int nastavnik_id, String prezime) {
        boolean rez = false;
        String upit = "UPDATE NASTAVNIK SET prezime=? WHERE nastavnik_id=?";

        try {
            pst = DBConnection.getConnection().prepareStatement(upit);
            pst.setString(1, prezime);
            pst.setInt(2, nastavnik_id);
            pst.executeUpdate();

            rez = true;
        } catch(Exception e) {
            System.err.println(e.getMessage());
        } finally {
            if (pst != null) {
                try {
                    pst.close();
                } catch (SQLException e) {
                    System.err.println(e.getMessage());
                }
            }

            return rez;
        }


    }
}