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

What is the type of kode_kelas in mahasiswa_kelas table? Look at what mysqli_query returns into $result with a var_dump. — Nicholas Alexander
– Nicholas Alexander, Commented May 28, 2016 at 9:20
mysql_query should return FALSE on error (i.e. an int) or a resource that can be used to get results: see php.net/manual/en/mysqli.quickstart.statements.php - I think you are being tripped up by a returned error condition but I strongly encourage understanding is the real answer here. — Nicholas Alexander
– Nicholas Alexander, Commented May 28, 2016 at 9:48

dg4220 · Accepted Answer · 2016-05-28 23:58:33Z

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);

edited May 28, 2016 at 23:58

answered May 28, 2016 at 9:47

dg4220

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12 Comments

Grace Michelle Over a year ago

So, can I use this? mixed mysqli_fetch_row ( mysqli_result $result )

dg4220 Over a year ago

Just to clarify mysqli_query() returns an object. mysqli_fetch_row() 'Get a result row as an enumerated array'. The data you're trying to insert is in the elements of the array so, loop the array, assign the the values to variables and insert those variables into your db with $sql2. There are more efficient ways to do it but editing your method this is what you ned to do.

Grace Michelle Over a year ago

Sorry, but I'm still confused with this. So, can you please update your answer & answer my question directly? Then, explain from your code. Maybe, I can understand more with that way. Thanks

Grace Michelle Over a year ago

Your code has no error, but the inputed data still aren't stored to database

dg4220 Over a year ago

use var_dump($result); and var_dump($row); to see what's in those values. it seems you may not have any results from $sql.

|

Kaja Mydeen · Accepted Answer · 2016-05-28 11:34:54Z

0

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.

answered May 28, 2016 at 11:34

Kaja Mydeen

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2 Comments

Grace Michelle Over a year ago

Can you give a more specific answer? Maybe you can answer my question directly?

Kaja Mydeen Over a year ago

i answered in next answer

Kaja Mydeen · Accepted Answer · 2016-05-30 05:00:38Z

0

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.

answered May 30, 2016 at 5:00

Kaja Mydeen

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