file upload tidak tampil dan tidak masuk database

Halo teman2 selamat siang, saya mau tanya nii saya ada masalah saat upload file ketika upload data file tidak masuk ke dalam database, ini kenapa ya teman2?

post file upload

<?php
include 'include/connection.php';

$nama_buku      = $_POST['nama_buku'];
$namaFile       = $_FILES['berkas']['size'];
$x              = explode('.',$namaFile);
$ekstensiFile   = strtolower(end($x));
$ukuranFile     = $_FILES['berkas']['size'];
$file_tmp       = $_FILES['berkas']['tmp_name'];

//lokasi penempatan file
$dirUpload      = "./file";
$linkBerkas     = $dirUpload.$namaFile;

//menyimpan File
$terupload      = move_uploaded_file($file_tmp,$linkBerkas);

$dataArr        = array(
    'tanggal'   => $tanggal,
    'nama_buku' => $nama_buku,
    'size'      => $ukuranFile,
    'ekstensi'  => $ekstensiFile,
    'berkas'    => $linkBerkas,
);

if ($terupload && (insertData($dataArr) ==1)) {
    echo "Upload Berhasil!";
    header("Location: index.php", true, 301);
    exit();
} else {
    echo "Upload Gagal!";
    header("Location: upload_data.php", true, 301);
    exit();
}

?>

upload data

<form action="fileUpload.php" method="post" enctype="multipart/form-data">
                            <div class="card-body">
                                <div class="form-group">
                                    <label>Judul Buku :</label>
                                    <input type="text" name="nama_buku" class="form-control">
                                </div>
                                <div class="form-group">
                                    <label>Keterangan :</label>
                                    <input type="text" name="nama_buku" class="form-control">
                                </div>
                                <div class="form-group">
                                    <label>Upload File :</label>
                                    <div class="input-group">
                                        <div class="custom-file">
                                            <input type="file" name="berkas" accept="application/pdf" class="custom-file-input" id="">
                                            <label class="custom-file-label" for="exampleInputFile">Choose file</label>
                                        </div>
                                        <div class="input-group-append"></form>
                                    </div>
                                </div>
                            </div>
                        </div>
                        <!-- /.card-body -->
                        <div class="card-footer">
                            <button type="submit" class="btn btn-primary">Submit</button>
                        </section>
                    </div>