JDBC va ma'lumotlar bazasi

Daraja: Ilg'or

JDBC — Java'dan SQL bazaga ulanishning standart usuli. `Connection` ulanish, `PreparedStatement` so'rov, `ResultSet` natija. Har doim `PreparedStatement` ishlat — u SQL injection'dan himoya qiladi va tezroq. Ulanishni try-with-resources bilan yopish shart.

Tushuntirish

Kod misoli

String sql = "SELECT id, ism FROM talaba WHERE kurs = ?";

try (Connection con = DriverManager.getConnection(URL, USER, PASS);
     PreparedStatement ps = con.prepareStatement(sql)) {

    ps.setInt(1, 2);

    try (ResultSet rs = ps.executeQuery()) {
        while (rs.next()) {
            System.out.println(rs.getInt("id") + " — " + rs.getString("ism"));
        }
    }
} catch (SQLException e) {
    e.printStackTrace();
}

Keng tarqalgan xatolar

So'rovni satr birlashtirish bilan qurish (`"... = " + input`) — SQL injection.
Connection/ResultSet'ni yopmaslik — ulanishlar tugab qoladi.

Mashqlar

SQLite bazaga ulanib, jadval yaratib, 3 ta yozuv qo'sh.
CRUD (create/read/update/delete) to'rt metodini yoz.

Teglar: jdbc, sql, baza

Interaktiv ko'rinish (viktorina, izohlar, tarix)