Array based problem

[Seiruu]

Where to start.....well let's see. I'm sort of making a very simple version of a "shopping cart system". Now I have my product list, and ive added checkboxes next to each product with the value of their own product ID to the value of the checkbox.

What I want to do is to have all the checked boxes neatly into the next page where I can

1. draw the ID's out and grab data out of my db with the extracted ID's.

but more importantly
2. put the data in a new table that functions like a "cart".

My friend (who's pretty good with php) couldn't figure out what's wrong with the edited script (I started off pretty messy, and he was "fixing" it).

So while the input of the checkboxes could be read (through the means of echoing parts of the receiving script), I'd get a blank output when I'm really trying to extract the data out of my db.

Here's the code for the output, hope someone can help. And if not, still thanx for reading so far.

<?  

include("connect.php");   

$keuzearray    = $_POST['keuzearray'];   

$result = mysql_query("SELECT Naam, Product_ID FROM product")or die(mysql_error());  

echo "<table width=100%>";   

while($row = mysql_fetch_object($result))  

{  

echo "Row: ".$row->Product_ID;
    if(in_array($row->Product_ID, $keuzearray))  

    {  

        echo "<tr>";   

        echo "<td>Productnummer: ".$row->Product_ID."</td>";   

        echo "<td>Naam:  ".$row->Naam."</td>";  

        echo "</tr>";  

    }      

}  

echo "</table>";  

print_R($keuzearray);
?>  

  

For this example I marked the 5th checkbox from the 5 created and this was the output of the test echos

The output of the echo "Row: ".$row->Product_ID;
is this: Row: 1Row: 2Row: 3Row: 4Row: 5

And the output for the print_R($keuzearray);
is this: Array ( [0] => 5 )

I have also confirmed that the table name and the table fields are spelled correctly (and yes, that does include upper/lower case).

So hope someone can tell me why I'm not getting the data out of the query. It doesn't give any errors or anything

[Hawkee]

I don't have a solution to your specific problem, but I may have an alternate suggestion that will be better in the long run. Rather than select every row from the database, you might want to consider selecting on the rows from $keuzearray. I would make a dynamic SQL query that appends code like this:

where
Product_ID = '$keuzearray[0]'
or Product_ID = '$keuzearray[1]'

This way you don't have to compare the returned data. You'll know that the rows are the rows you need. Also, in larger databases, it's good to select only the data you need because mySQL will want to pass tons of unnecessary data to PHP when you only want a few fields.

Enjoy!
- Hawkee

[Kaastosti]

Hey 🙂

I've helped Seiruu with building this little piece of coding. He himself at first had, indeed, an array with values which he inserted into the sql query.

I agree that this won't be great for huge databases, since all data will be retreived at first. The other option, which you use, also has a disadvantage.

For every value in the array, you'll do a request to the database for information. I always try to minimize the amount of times that you have to request things from a database.

The way I work (which includes templates), everything gets cached, thus the huge amount of data only is retreived one time. After that (provided nothing has changed), the next user will simply receive the already cached html file.

Although this is a preferable method, I doubt that Seiruu is about to use templates. I shoul've seen this problem earlier...

However, since this is just a small project, the database won't be big. It won't even be small to my knowledge. In fact, it can hardly be called a database. Problems with huge amounts of data won't occur.

Still... the problem remains. I've been over this piece of code a few times now and really can't figure out exactly where the problem resides.

[kevinsequeira]

you mean to say the if condition doesnt evaluate to true when $row ->Product_ID = 5 ???
is that what the issue is ??

try
print (in_array($row->Product_ID, $keuzearray));

see what it prints out
or try this

<?php
while($row = mysql_fetch_array($result)){  

	echo "Row: ".$row['Product_ID'];
    if(in_array($row['Product_ID'], $keuzearray)){  

        echo "<tr>";   

        echo "<td>Productnummer: ".$row['Product_ID']."</td>";   

        echo "<td>Naam:  ".$row['Naam']."</td>";  

        echo "</tr>";  

    }      

}  

?>

reg
kevin

[tsinka]

Hi,

I think mysql_fetch_array is the wrong function in that place, use mysql_fetch_row if you want to fetch row by row. mysql_fetch_array fetches the complete result set into an array. You would have to loop through the fetched array if you use mysql_fetch_array.

[kevinsequeira]

it doesnt fetch the entire resultset!!!!

you dont need to loop thru the fetched array, u just acces it diretly like $row['column_name']

http://www.php.net/manual/function.mysql-fetch-array.php

and

http://www.php.net/manual/en/function.mysql-fetch-row.php

see the manual for the advantages of using mysql_fetch_array, though in this case it doesnt really make a differance.
reg
kevin

[Seiruu]

kevin

tried your code, still giving blank results.

I don't get it. Everything else works, the table name is correct, the fields are correct. Now why doesn't it return anything....