PHP - Insert to Database Using Another Table

Question

I make 2 forms in 3 files: loginMHS.php , inputPerwalian.php , insertMataKuliah.php .

I have 4 tables in database: mahasiswa , matakuliah , kelas , mahasiswa_kelas .

mahasiswa table has these fields:

nrp | nama | pass | jatah_sks | foto_profil

matakuliah table has these fields:

kode_mk | nama | jumlah_sks | deskripsi

kelas table has these fields:

kode_kelas | kode_mk | kode_periode | nama_kelas

mahasiswa_kelas table has these fields:

nrp | kode_kelas

First, loginMHS.php showed up. It has a form, which has an input stored in var $nrp (from mahasiswa table). After login, inputPerwalian.php showed up. It has a form too, which has inputs stored in var $kodeMK (from matakuliah table) & $namaKelas (from kelas table). Then, the inputs will be inserted to table mahasiswa_kelas .

This is my code (the inputs can't be stored to DB, but it shows no error):

$sql = "select kode_kelas from kelas inner join mahasiswa_kelas"
       . " on kelas.kode_kelas = mahasiswa_kelas.kode_kelas"
       . " where nama_kelas=" . $namaKelas;
$result = mysqli_query($link, $sql);

$sql2 = "insert into mahasiswa_kelas (nrp, kode_kelas)"
        . " values ($nrp, $result)";
$result2 = mysqli_query($link, $sql2);
$row2 = mysqli_fetch_array($result2);

I don't know how to insert it, while the data inputed is from another table. Because, from what I know is, I can't use inner join in insert query. How to solve it? Please explain your answer. Thanks

Answer 1

mysqli_query() returns an object so you can't insert $result as a value. Check out how they handle it in the manual with mysqli_fetch_row This should take care of your problem

Update: Not sure what you mean by 'use' but I think not . . . keep reading. You need to parse your array from mysqli_fetch_row() . Look at

if ($result = mysqli_query($link, $query)) {

/* fetch associative array */ 
while ($row = mysqli_fetch_row($result)) {
printf ("%s (%s)\n", $row[0], $row[1]); 
} 
free result set */ mysqli_free_result($result);

}`

Update 2: Not sure if I should be writing the code for you but here you go. As described mysqli_query() returns $result as an object. mysqli_fetch_row() returns $result as an array. Get your value from the proper array index and assign to a variable $kode_kelas_value . Insert that variable into the db with your $sql2 query.

$sql = "select kode_kelas from kelas inner join mahasiswa_kelas"
       . " on kelas.kode_kelas = mahasiswa_kelas.kode_kelas"
       . " where nama_kelas=" . $namaKelas;
if ($result = mysqli_query($link, $sql)) {

    while ($row = mysqli_fetch_row($result)) {
        $kode_kelas_value = $row[0];
    } 
    /*free result set */
    mysqli_free_result($result);

}`

    $sql2 = "insert into mahasiswa_kelas (nrp, kode_kelas)"
            . " values ($nrp, $kode_kelas_value)";
    $result2 = mysqli_query($link, $sql2);
    $row2 = mysqli_fetch_array($result2);

Answer 2

you should fetch nrp, kode_kelas values by using join query. If you got those values perfectly then you can insert simply know. Any queries ask me.

Answer 3

First you can get nrp value from loginMHS.php. You have to pass that nrp value to inputPerwalian.php. In inputPerwalian.php you can get value for kodemk. if you submit that form u will get 2 important needed data that are nrp and kodemk. Now u would have nrp and kodemk.

now you have to insert into mahasiswa_kelas with nrp, kode_kelas. Already you have nrp, but u dont have kode_kelas. in order to get kode_kelas value you have to select kode_kelas data from kelas table by select query.

"SELECT kode_kelas FROM kelas where kode_mk = kodemk "

By using this query you can get kode_kelas value.

Now you can insert nrp and kode_kelas values in mahasiswa_kelas.

Hope it will helpful.