act_input_transaksi.php

<?php
$tgl_pinjam     = isset($_POST['pinjam']) ? $_POST['pinjam'] : "";
$tgl_kembali    = isset($_POST['kembali']) ? $_POST['kembali'] : "";
$dapat          = isset($_POST['buku']) ? $_POST['buku'] : "";
$pecah          = explode (".", $dapat);
$id             = $pecah[0];
$buku           = $pecah[1];
$siswa          = isset($_POST['peminjam']) ? $_POST['peminjam'] : "";
$ket            = isset($_POST['ket']) ? $_POST['ket'] : "";
if($buku == "" || $dapat == "") {
    echo "<script>alert('Pilih dulu BUKU-nya, Bos!!');</script>";
    echo "<meta http-equiv='refresh' content='0; url=?page=input_transaksi'>";
} elseif ($siswa=="") {
    echo "<script>alert('Pilih dulu PEMINJAM-nya, Bos!!');</script>";
    echo "<meta http-equiv='refresh' content='0; url=?page=input_transaksi'>";
} else {
    include "../include/koneksi_db.php";
    $query=mysql_query("SELECT * FROM data_buku WHERE judul = '$buku'", $konek);
    while ($hasil=mysql_fetch_array($query)) {
        $sisa=$hasil['jum_temp'];
    }

    if ($sisa == 0) {
        echo "<script>alert('SORY BOS, Bukunya telah habis...!. Anda tidak bisa melakukan transaksi !');</script>";
        echo "<meta http-equiv='refresh' content='0; url=?page=transaksi'>";
    } else {
        $qt         = mysql_query("INSERT INTO trans_pinjam VALUES (null, '$buku', '$id', '$siswa', '$tgl_pinjam', '$tgl_kembali', 'pinjam', '$ket')", $konek) or die ("Gagal Masuk".mysql_error());
        $qu         = mysql_query("UPDATE data_buku SET jum_temp=(jum_temp-1) WHERE id=$id ", $konek);
        if ($qt&&$qu) {
            echo "<script>alert('Transaksi BERHASIL...');</script>";
            echo "<meta http-equiv='refresh' content='0; url=?page=transaksi'>";
        } else {
            echo "<script>alert('Transaksi GAGAL...');</script>";
            echo "<meta http-equiv='refresh' content='0; url=?page=input_transaksi'>";
        }
    }
}
?>