Delete items unchecked from a form using ColdFusion - coldfusion

Question

When a user deselects an item (by unchecking the checkbox) from the form, I want the corresponding data to be deleted from the database.
Here is what my form looks like:
Category
Item 80 626
1.Item # 1 (87) chk chk
2.Item # 2 (59) chk chk
So basically, the list looks like this:
DB_list = (80|87, 626|87, 80|59, 626|59)
Now if a user deselects one of these items 80|87, I want it to be deleted from the database like so:
DELETE FROM TBL
WHERE Item = 87
AND Category = 80
So on form submit, the list becomes
New_List = (626|87, 80|59, 626|59)
How do we delete 80|87?

Answer 1

This is one way to do it:
<cfoutput>
<cfset DB_list = "80|87,626|87,80|59,626|59" />
<cfset New_List = DB_list />
<cfset myitems="80,626">
<cfset mycategories = "87,59"/>
<cfif structKeyExists(form,"fieldnames")>
<!-- on submit -->
<cfif structKeyExists(form,"listitem")>
<cfset New_List = form.listitem>
</cfif>
<br />RESULT:<br />
DB_list:#DB_list#<br />
New_List:#New_List# <br /><br />
<cfloop from="1" to="#ListLen(DB_list)#" index="ix">
<cfset listitem = ListGetAt(DB_list,ix)>
<cfif ListFindNoCase(New_List,listitem) eq 0>
<!-- hence: split in javascript -->
<cfset listitemarray=ListToArray(listitem,"|")/>
<cfset itemid=listitemarray[1] />
<cfset categoryid=listitemarray[2] />
<cfquery>
DELETE FROM TBL
WHERE Item = <cfqueryparam cfsqltype="CF_SQL_INTEGER" value="#itemid#">
AND Category = <cfqueryparam cfsqltype="CF_SQL_INTEGER" value="#categoryid#">
</cfquery>
</cfif>
</cfloop>
</cfif>
<form name="tstForm" id="tstForm" method="post" action="">
<table>
<tr>
<td> </td>
<cfloop from="1" to="#ListLen(mycategories)#" index="lstindex1">
<td>Category #ListGetAt(mycategories,lstindex1)#</td>
</cfloop>
</tr>
<cfloop from="1" to="#ListLen(myitems)#" index="lstindex2">
<tr>
<cfset itemid=#ListGetAt(myitems,lstindex2)# />
<td>item #itemid#</td>
<cfloop from="1" to="#ListLen(mycategories)#" index="lstindex3">
<cfset catid=#ListGetAt(mycategories,lstindex3)# />
<td>
<input type="checkbox" id="listitem_#itemid#_#catid#" name="listitem" value="#itemid#|#catid#" <cfif ListFindNoCase(New_List,"#itemid#|#catid#",",") gt 0>checked</cfif>/>
</td>
</cfloop>
</tr>
</cfloop>
</table>
<button type="submit">Submit</button>
</form>
</cfoutput>
Run this code here

Answer 2

My approach would be to have a hidden field in the form that has all the available values for the checkboxes. Then when the form is submitted, compare what's in the hidden form field with what's in the checkbox field. Whatever the hidden field has that the check box field does not can be deleted.

Answer 3

Without the use of JavaScript, Dan Bracuk's solution would work the best for your stated requirements. However, another simpler approach to this problem is to just delete all previous choices then re-insert whatever items are still checked. Then there is no need to compare old and new values to determine what has changed.

Answer 4

How about
DELETE
FROM tbl
WHERE NOT CONVERT(varchar(20), Item) + '|' + CONVERT(varchar(20), Category)
IN <cfqueryparam cfsqltype="CF_SQL_varchar" value="#form.new_list#" list="yes">

Answer 5

My approach using sql server is to delete all the list items from the db, and then add only the ones that have been submitted by the form. All delete and add queries should be put into a single transaction, so if anything fails you can make o rollback.