DELETE
FROM table
WHERE table_id = variable_id

In writing a component for some of the tools I started wondering if, in addition to data, I could also pass the names of database tables and columns to create an all-purpose generic delete function.
I started by created a generic component, generic.cfc and wrote my function:

<cffunction name=”deleteRecordByID” access=”public” returntype=”Boolean”
hint=”Deletes a record from a passed table based on passed id” >
<cfargument name=”tableName” type=”string” required=”yes” />
<cfargument name=”idColumnName” type=”string” required=”yes” />
<cfargument name=”idValue” type=”numeric” required=”yes” />
<cfargument name=”dsn” type=”string” required=”no” default=”myDSN” />
<cftry>
<cfquery name=”qDelRecord” datasource=”#arguments.dsn#”>
DELETE
FROM #arguments.tableName#
WHERE #arguments.idColumnName# = <cfqueryparam value=”#arguments.idValue#” cfsqltype=”cf_sql_integer”>
</cfquery>
<cfcatch type=”any”>
<cfreturn false />
</cfcatch>
</cftry>
<cfreturn true />
</cffunction>

Then I gave it a shot:

<cfset objGeneric = createObject(“component”,”generic”) />
<cfset deleteResult = objGlobal.deleteRecordByID(“myTableName”, “myTableIDColumn”, idValue, request.dsn) />

To my surprise, er I mean just as I expected, it was successful. Whether you find the deleteByRecordID function clever or utterly ridiculous, the knowledge that you can pass database object names for query execution can be useful.

-rG

After about an hour of playing with it I was able to get the code working properly and I thought I’d share a very basic example. The following code queries a database for names and phone numbers then outputs them all to a file name phonelist.xml in the current path:

<cfquery name="qGetPhoneList" datasource="datasource">
select first_name,last_name,phone from employees
</cfquery>

<!—Create a temporary variable "tempxml" to hold our XML document—>

<cfset tempxml = "<?xml version =""1.0""?>
<!DOCTYPE phonelist [
<!ELEMENT phonelist (firstname,lastname,phone)>
]>
<phonelist>">
<cfloop query="qGetPhoneList">
<cfset tempxml = "#tempxml#
<cid>#Trim("#XMLFormat(first_name)#")#</cid>
<s>#Trim("#XMLFormat(last_name)#")#</s>
<r>#Trim("#XMLFormat(phone)#")#</r>
">
</cfloop>
<cfset tempxml = "
#tempxml#
</phonelist>">

<!—show the XML in the HTML output —>
<P>This is a simple XML document that’s been generated by the ColdFusion code. </P>
<cfoutput>
<xmp>
#tempxml#
</xmp>
</cfoutput>

<!—write out the XML—>
<cfset writePath=#ExpandPath("phonelist.xml")#>
<cfoutput>
#writePath#<br />
<cffile action = "Write" file="#writePath#" output="#tempxml#">
</cfoutput>

-rG