Web Site Cookbook

7.6. Storing Multiple Values in One Database Field

Problem

You need to store multiple answers from one form question in a single database field.

Solution

Set up your multi-input form fields to pass their values as an array by adding opening and closing bracket characters to the field name, like this:

	<input type="checkbox" name="favcolors[]" value="Red">Red

Then use PHP's built-in implode( ) function to convert the array to a string separated by a unique character before storing the string in a single database field. In this Recipe, I'll use the pipe character (|) to separate unique values in the array-turned-string:

	$favcolors_imp = implode("|",$favcolors);

Then you can insert the string $favcolors_imp into a text or varchar field in your SQL database.

If you need to convert the string back to an array, use the PHP explode function:

	$favcolors_exp = explode("|",$favcolors_imp);

Discussion

HTML provides two form elements that allow users to select multiple choices: the checklist created with the input type="checkbox" tag shown above, and the multi-option select list created with this code:

	<select name="favcolors[]" size="10" multiple>
	 <option value="Green" label=" Green ">Green</option>
	 <option value="Black" label=" Black ">Black</option>
	 <option value="Brown" label="Brown">Brown</option>
	</select>

The rendered versions of each type of list are shown in Figure 7-5.

Figure 7-5. What's your ...