src/model/TeachingManager.java - master - Maksim_Shchelochok/Course_Work

src/model/TeachingManager.java
128 строк5 KB
Maksim
Исправление орфографических ошибок
26 июн 2026, 02:27
26 июн 2026, 02:27e1279cb
package model;

import util.ConnectDatabase;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class TeachingManager {

    private Connection getConnection() {
        return ConnectDatabase.getInstance().getConnection();
    }

    public List<Teaching> getAll() {
        List<Teaching> list = new ArrayList<>();
        String sql = "SELECT t.teaching_id, t.teacher_id, " +
                "CONCAT(te.last_name, ' ', te.first_name) AS teacher_name, " +
                "t.group_id, t.hours_count " +
                "FROM teachings t " +
                "JOIN teachers te ON t.teacher_id = te.teacher_id " +
                "ORDER BY t.teaching_id";
        try (PreparedStatement ps = getConnection().prepareStatement(sql);
             ResultSet rs = ps.executeQuery()) {
            while (rs.next()) {
                list.add(new Teaching(
                        rs.getInt("teaching_id"),
                        rs.getInt("teacher_id"),
                        rs.getString("teacher_name"),
                        rs.getInt("group_id"),
                        rs.getInt("hours_count")));
            }
        } catch (SQLException e) {
            System.out.println("Ошибка чтения преподавателей: " + e.getMessage());
        }
        return list;
    }

    public List<Teacher> getAllTeachers() {
        List<Teacher> list = new ArrayList<>();
        String sql = "SELECT teacher_id, last_name, first_name, patronymic, " +
                "work_experience, phone_number FROM teachers ORDER BY last_name";
        try (PreparedStatement ps = getConnection().prepareStatement(sql);
             ResultSet rs = ps.executeQuery()) {
            while (rs.next()) {
                list.add(new Teacher(
                        rs.getInt("teacher_id"),
                        rs.getString("last_name"),
                        rs.getString("first_name"),
                        rs.getString("patronymic"),
                        rs.getInt("work_experience"),
                        rs.getString("phone_number")));
            }
        } catch (SQLException e) {
            System.out.println("Ошибка чтения преподавателей: " + e.getMessage());
        }
        return list;
    }

    public List<Group> getAllGroups() {
        List<Group> list = new ArrayList<>();
        String sql = "SELECT g.group_id, g.students_count, g.specialty_id, " +
                "s.name AS specialty_name " +
                "FROM `groups` g " +
                "JOIN specialties s ON g.specialty_id = s.specialty_id " +
                "ORDER BY g.group_id";
        try (PreparedStatement ps = getConnection().prepareStatement(sql);
             ResultSet rs = ps.executeQuery()) {
            while (rs.next()) {
                list.add(new Group(
                        rs.getInt("group_id"),
                        rs.getInt("students_count"),
                        rs.getInt("specialty_id"),
                        rs.getString("specialty_name")));
            }
        } catch (SQLException e) {
            System.out.println("Ошибка чтения групп: " + e.getMessage());
        }
        return list;
    }

    public String create(int teacherId, int groupId, int hoursCount) {
        if (hoursCount <= 0) {
            return "Количество часов должно быть больше нуля.";
        }
        String sql = "INSERT INTO teachings (teacher_id, group_id, hours_count) VALUES (?, ?, ?)";
        try (PreparedStatement ps = getConnection().prepareStatement(sql)) {
            ps.setInt(1, teacherId);
            ps.setInt(2, groupId);
            ps.setInt(3, hoursCount);
            ps.executeUpdate();
            return null;
        } catch (SQLException e) {
            return "Ошибка добавления: " + e.getMessage();
        }
    }

    public String update(int id, int teacherId, int groupId, int hoursCount) {
        if (hoursCount <= 0) {
            return "Количество часов должно быть больше нуля.";
        }
        String sql = "UPDATE teachings SET teacher_id = ?, group_id = ?, hours_count = ? " +
                "WHERE teaching_id = ?";
        try (PreparedStatement ps = getConnection().prepareStatement(sql)) {
            ps.setInt(1, teacherId);
            ps.setInt(2, groupId);
            ps.setInt(3, hoursCount);
            ps.setInt(4, id);
            ps.executeUpdate();
            return null;
        } catch (SQLException e) {
            return "Ошибка изменения: " + e.getMessage();
        }
    }

    public String delete(int id) {
        String sql = "DELETE FROM teachings WHERE teaching_id = ?";
        try (PreparedStatement ps = getConnection().prepareStatement(sql)) {
            ps.setInt(1, id);
            ps.executeUpdate();
            return null;
        } catch (SQLException e) {
            return "Не удалось удалить: " + e.getMessage();
        }
    }
}