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Ben Nadel at NCDevCon 2016 (Raleigh, NC) with: Masha Edelen
Ben Nadel at NCDevCon 2016 (Raleigh, NC) with: Masha Edelen ( @mashaedelen )

Ray Camden's Friday Puzzler - Compare Directories

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Ray Camden put up a Friday Puzzler to compare directories. This felt like a place to quickly throw some ColdFusion query of queries together. This solution will work with small directories, but certainly, I doubt that this will scale nicely as it would end up generating ENORMOUSLY SQL statements.

To start off with, I created two small directories:

Directory A:

  • \A\20071207.txt
  • \A\a-only.txt
  • \A\duplicate_file.txt

Directory B:

  • \B\20071207.txt
  • \B\b-only.txt
  • \B\duplicate_file.txt

Each directory has a file that is unique to them (a-only.txt and b-only.txt). Each on has a duplicate file (duplicate_file.txt). And, each on of them has a duplicate file that is a different size (20071207.txt). To compare these two directories from the directory, I ran this code:

<!--- Query files from directory A. --->
<cfdirectory
	action="list"
	directory="#ExpandPath( './A/' )#"
	name="qA"
	/>


<!--- Query files from directory B. --->
<cfdirectory
	action="list"
	directory="#ExpandPath( './B/' )#"
	name="qB"
	/>


<!--- Query for files that are in A, but not in B. --->
<cfquery name="qAOnly" dbtype="query">
	SELECT
		[name]
	FROM
		qA
	WHERE
		[type] = 'File'
	AND
		(
				1 = 1

			<!---
				Make sure the current A record does NOT
				match any records in the B query.
			--->
			<cfloop query="qB">

				AND
					[name] != '#qB.name#'

			</cfloop>
		)
</cfquery>


<!--- Query for files that are in B, but not in B. --->
<cfquery name="qBOnly" dbtype="query">
	SELECT
		[name]
	FROM
		qB
	WHERE
		[type] = 'File'
	AND
		(
				1 = 1

			<!---
				Make sure the current B record does NOT
				match any records in the A query.
			--->
			<cfloop query="qA">

				AND
					[name] != '#qA.name#'

			</cfloop>
		)
</cfquery>


<!---
	Query for files that are both in A and B, but not
	on the same date or size.
--->
<cfquery name="qBoth" dbtype="query">
	SELECT
		qA.[name]
	FROM
		qA,
		qB
	WHERE
		qA.[type] = 'File'
	AND
		qA.[name] = qB.[name]
	AND
		(
				qA.datelastmodified != qB.datelastmodified
			OR
				qA.size != qB.size
		)
</cfquery>



<!--- Dump out results. --->
<cfdump
	var="#qAOnly#"
	label="Directory A Only"
	/>

<br />

<cfdump
	var="#qBOnly#"
	label="Directory B Only"
	/>

<br />

<cfdump
	var="#qBoth#"
	label="Both But Different"
	/>

When we run that, we get this CFDump output:

Directory Compare Using ColdFusion Query of Queries

So, it works for small little directory compares. I know anything about File Diffs or Directory Diffs, so I am sure that there are way more optimized ways of doing this. But, ColdFusion query of queries makes this a rather easy task.

Want to use code from this post? Check out the license.

Reader Comments

15,674 Comments

@Rick,

Your solution is very good. My hat is off to you, good sir. It's nice to see someone who really knows how to leverage ColdFusion query of queries. Sometimes I think they are one of the unsung heroes of ColdFusion.

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Ben Nadel