Multipe Insert Data

Asalamualikum Semua...

kali ini saya akan melakukan insert multipe dengan menggunakan multipe select akan tetapi ada kendala di saat melakukan hal tersebut dimana

jika saya melakukan select barang hanya satu barang akan muncul error seperti berikut "Cannot add or update a child row: a foreign key constraint fails (`_2login`.`tb_pinjamkbm`, CONSTRAINT `tb_pinjamkbm_ibfk_2` FOREIGN KEY (`id_jadwal`) REFERENCES `tb_jadwal` (`id_jadwal`)) "

Namun Jika Barang Yang Di input dua barang maka yang akan masuk 3 barang

berikut struktu tabel yang saya miliki tabel pkbm "id_pkbm (Primary),id (FK),id_siswa (FK),id_jadwal (FK),tgl_pinjam,tgl_kembali,bts_pinjam,pinjam_status"

tabel jadwal "id_jadwal (Primary),hari ,jam,jam_mulai,jam_selesai,kd_mapel (FK),kd_guru (FK),id_kelas (FK)"

Berikut Script Nya

// Form Input
<form action="" method="POST" autocomplete="off">
                    <div class="row">
                        <div class="form-group col-4">
                            <label for="id_siswa">Nama Siswa</label>
                            <select name="id_siswa" id="id_siswa" class="form-control" required>
                                <option value="" hidden>Pilih Siswa</option>
                                <?php
                                $siswa = $conn->query("SELECT * FROM tb_siswa");
                                while ($as = $siswa->fetch_array()) : ?>
                                    <option value="<?= $as['id_siswa']; ?>">
                                        <?= $as['siswa']; ?>
                                    </option>
                                <?php endwhile; ?>
                            </select>
                        </div>
                        <div class="form-group col-4">
                            <label for="id_jadwal">Kelas</label>
                            <select name="id_jadwal" id="id_jadwal" class="form-control" required>
                                <option value="" hidden>Pilih Kelas</option>
                                <?php
                                $kelas = $conn->query("SELECT * FROM tb_jadwal INNER JOIN tb_kelas ON tb_jadwal.id_kelas = tb_kelas.id_kelas");
                                while ($as = $kelas->fetch_array()) : ?>
                                    <option value="<?= $as['id_jadwal']; ?>">
                                        <?= $as['kelas']; ?>
                                    </option>
                                <?php endwhile; ?>
                            </select>
                        </div>
                    </div>
                    <!--  -->
                    <div class=" form-group">
                        <label class="">Pilih Barang</label>
                        <label for="" class="col-md-8">
                            <select name="id[]" class="form-control select2" multiple="multipe">
                                <option value="">Pilih Barang</option>
                                <?php
                                $query = ("SELECT * FROM tb_sarpases WHERE status = 'tampilkan'");
                                $query_run = mysqli_query($conn, $query);
                                if (mysqli_num_rows($query_run) > 0) {
                                    foreach ($query_run as $row) {
                                ?>
                                        <option value="<?= $row['id']; ?>">
                                            <?= $row['nama_sarpras']; ?>
                                        </option>
                                    <?php
                                    }
                                } else {
                                    ?>
                                    <option value="">Data Tidak Ada</option>
                                <?php
                                }
                                ?>
                            </select>
                        </label>
                    </div>
                    <div class="row">
                        <div class="form-group col-4">
                            <label for="nis" class="d-block">Batas Jam Pinjam</label>
                            <div class="selectgroup selectgroup-pills">
                                <label class="selectgroup-item">
                                    <input type="radio" name="bts_pinjam" value="2" class="selectgroup-input">
                                    <span class="selectgroup-button selectgroup-button-icon"><i class="far fa-clock"> Jam ke 2</i></span>
                                </label>
                                <label class="selectgroup-item">
                                    <input type="radio" name="bts_pinjam" value="4" class="selectgroup-input">
                                    <span class="selectgroup-button selectgroup-button-icon"><i class="far fa-clock"> Jam ke 4</i></span>
                                </label>
                                <label class="selectgroup-item">
                                    <input type="radio" name="bts_pinjam" value="6" class="selectgroup-input">
                                    <span class="selectgroup-button selectgroup-button-icon"><i class="far fa-clock"> Jam ke 6</i></span>
                                </label>
                            </div>
                        </div>
                    </div>
                    <!-- <div class="form-group">
                        <label class="col-md-12">keterangan</label>
                        <div class="col-md-8">
                            <input type="text" value="-" name="keterangan" class="form-control">
                        </div>
                    </div> -->
                    <div>
                        <button type="submit" name="add" value="Save" class="btn btn-success"><i class="fas fa-paper-plane"></i>Save</button>
                        <button type="reset" class="btn btn-secondary">Reset</button>
                    </div>
                </form>

Query insertnya

<?php
                if (isset($_POST['add'])) {
                    $siswa = $_POST['id_siswa'];
                    $id_jadwal = $_POST['id_jadwal'];
                    $id = $_POST['id'];
                    $batas = $_POST['bts_pinjam'];
                    foreach ($id as $barangs) {
                        $query = "INSERT INTO tb_pinjamkbm (id_siswa,id,id_jadwal,bts_pinjam) VALUES ('$siswa','$barangs','$batas','$id_jadwal')";
                        $query_qu = mysqli_query($conn, $query);
                    }
                    $query_qu = mysqli_query($conn, $query);
                    if ($query_qu) {
                        echo "<script>alert('Data berhasil ditambah.😃😃😃');window.location='?page=pkbm';</script>";
                        // jika query salah munculkan pesan data gagal di simpan lalu redirec ke halaman dashbord
                    } else {
                        echo mysqli_error($conn);
                    }
                }
                ?>