How do you manage transactions in JDBC? JDBC में transactions कैसे manage करें?

Transactions group multiple SQL operations so they either all succeed (commit) or all fail together (rollback), preserving data consistency. JDBC connections are in auto-commit mode by default, which must be disabled to manage transactions manually.

Connection conn = null;
try {
    conn = DriverManager.getConnection(url, user, password);
    conn.setAutoCommit(false);  // start manual transaction control

    PreparedStatement debit = conn.prepareStatement(
        'UPDATE accounts SET balance = balance - ? WHERE id = ?');
    debit.setDouble(1, 100);
    debit.setInt(2, fromAccountId);
    debit.executeUpdate();

    PreparedStatement credit = conn.prepareStatement(
        'UPDATE accounts SET balance = balance + ? WHERE id = ?');
    credit.setDouble(1, 100);
    credit.setInt(2, toAccountId);
    credit.executeUpdate();

    conn.commit();  // both updates succeed together
    System.out.println('Transfer successful');

} catch (SQLException e) {
    if (conn != null) {
        try {
            conn.rollback();  // undo BOTH updates if anything failed
            System.out.println('Transaction rolled back');
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
    }
} finally {
    if (conn != null) {
        try {
            conn.setAutoCommit(true);  // restore default behavior
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

// Savepoints - partial rollback within a larger transaction
Savepoint savepoint = conn.setSavepoint('beforeRiskyOperation');
try {
    // risky operation
} catch (SQLException e) {
    conn.rollback(savepoint);  // rolls back only to the savepoint, not the whole transaction
}