help with drop down box for choosing which database to query

vesper8

hello.. this should be trivial but.. i am new.. and i'm having a brain cramp over this.. so please help anyone if you've got a minute or two to spare

i'm trying to create a very simple single drop-down box that lets me choose which database i want to use for my query

i want the page to reload itself once the selection is made.. since this is all part of the same php file

and what i'm having trouble with also is getting the value from the js form to be sent over to my php code

here's what i got so far.. but it ain't much

<select name="my_select_box">
<OPTION SELECTED>Select a Database
<OPTION Value="database_1">1
<OPTION Value="database_2">2
<OPTION Value="database_3">3
</SELECT>
<input type="button" Value="GO" onClick="window.location.reload()">

and my query looks like this

$sql = "SELECT * FROM ".$_POST[my_select_box].$orderByQuery.$limitQuery;

i'm now trying to get this to work with the $_POST.. at first I was trying to just get the value from my dropdown to be inserted into a standard php variable.. but either way.. nothing is working.. when i click on the GO button well... nothing happens

how would i set one of the values as a default value also? so my page doesn't show errors when loading it for the first time since the sql query is missing the database name

Houdini

What is the action ="" go to or do you have an action for the form?
Use <OPTION SELECTED> (and whatever you want for a default)

vesper8

umm.. that's the thing.. i guess i don't fully understand how forms work.. but um.. when i press GO.. i just assumed it would do the onClick page reload.. and i'm not even sure if that's doing it right.. but in any case.. it does neither

vesper8

can anyone help?

Houdini

Look at a simple example;

<html>
<body>
<form name="test" action="process.php" method="post">
First Name<input type="text" name="first_name">
Last Namd<input type="text" name="last_name">
Age<input type="text" name="age">
<input type ="submit" value="Enter Info">
</body>
</html>

This form uses 'process.php' for the action to be taken when submitted so we need another file named 'process.php' that will do something when the Enter Info button is pressed or clicked. So lets make it, then you can run it

<?php //process.php
echo "Hello $_POST[first_name] you entered $_POST[last_name] as <br>";
echo "your last name and you said you were $_POST[age] years old!<br>";
echo "Thanks for coming to this site and filling in the form ..........";
//You could add more processing like run an sql query or whatever
//This just show what the action of the form does it calls this file.
?>

In selection drop downs any OPTION that states <OPTION SELECTED value="some option">Some option would be what you see in the selection list and its value would be entered if the user did not select anything, or left the form as is.

skdzines

This is how I like to do things. Add the following code to your page.

<?
if(!isset($form)){
   echo"
   <form name='chooseDB' method='post' action='$PHP_SELF'>
            <select name='my_select_db' onChange='this.form.submit();'>
            <option selected>Select a Database</a>
            <option value='database_1'>1</option>
            <option value='database_2'>2</option>
            <option value='database_3'>3</option>
            </select>
   <input type='hidden' name='form' value='continue'/>
   </form>";
}elseif($form == "continue"){
   $sql = "Select * from ".$my_select_db."";
   $query = mysql_query($sql);
   $result = mysql_fetch_row($query);

  echo" some result";  // depending on the information you are trying to receive, you will echo out those results here.
}
?>

The first time you access the page, the variable $form will not be set, once you select a db from the list, this will call the onChange function and recall the page via $PHP_SELF. Now the var $form will be set to "continue" and will now query the database

Hope this helps.

frost110

To set a value as default value, a loop of sometype works good along with an array of data:

This scenario the user selected site2 and for some reason had to go back due to an error.

$ar = array("http://www.siteone.com", "http://www.site2.com", "http://www.site3.com");

foreach ($ar as $key => $site) {
         if ($_POST['site_drop_down'] == $site) {
                $input .= '<option value="'.$site.'" selected>'.$site.'</option>';
         }else {

     }
}

frost110

To set a value as default value, a loop of sometype works good along with an array of data:

This scenario the user selected site2 and for some reason had to go back due to an error.

$ar = array("http://www.siteone.com", "http://www.site2.com", "http://www.site3.com");
$input = '<select name="site_drop_down">';
foreach ($ar as $key => $site) {
         $selected = "";
         if ($_POST['site_drop_down'] == $site) {
                $selected = "selected";
         }
         $input .= '<option value="'.$site.'" '.$selected.'>'.$site.'</option>';
}

print $input . "</select>";

Simple as that. The $ar can be retrieved from a DB if needed. This works great for large lists like Countries or States which you might keep in a database or text file.

--FrosT