Sure...
I see, Thanks Pete.
A Cached Array for persistent data which is index pointers so to speak... yep makes
sense.
Ok... NOW, Thinking deeper...
How are people handling Multi-User concurrency issues? How to not overwrite someone
elses changes to a record while pondering how to make your own changes to the
record....
IE:
User A reads Record #1.
User B reads record #1.
User B changes fields[3,4,5] in Record #1 and rewrites the entire record.
User A changes fields[7,8,9] in Record #1 and overwrites [3,4,5] with old data just
changed by User B.
In the past I have used the Classic
Lock/ReReadRecord/ModifyMyChangedFieldsOnly/WriteRecord/UnLock scenario to avoid this
via built in tools...
What does CF have built in or in the way of custom tags to help with this?
At 04:01 PM 8/31/01 -0400, you wrote:
>Gonzo,
>
> There are cases where building a cached array is more efficient. Mainly
>when you want indexed Access to records (basically your not going to output
>all your data at once).
>
>So consider the following situation lets say you had a table called
>documents that you accessed the following way...
>/getDocument.cfm?DocumentID=12 and it would pull the document from the db
>with that ID out and display it. If you had a cached query your going to
>have to loop through it and find the correct document (or do a query of a
>query). It's much faster to access an array element here than perform this
>comparison.
>
>Here's how you might build such an array, for this general document example:
>
>put this in application.cfm ...
>
>
><cflock scope="application" type="exclusive" timeout="20">
><cfif NOT IsDefined("application.document")>
> <cfquery datasource="dsn" name="doc">
> SELECT DocumentID, Name, Description, Content
> FROM documents
> </cfquery>
>
> <cfset application.document = ArrayNew(1)>
> <cfoutput query="doc">
> <cfscript>
> application.document[DocumentID] = StructNew();
> application.document[DocumentID].Name = doc.Name;
> application.document[DocumentID].Description = doc.Description;
> application.document[DocumentID].Content = doc.Content;
> </cfscript>
> </cfoutput>
></cfif>
>
></cflock>
>
>
>Now to access an element, something like this...
>
><cflock scope="application" type="readonly" timeout="20">
> <cfoutput>#application.document[url.DocmentID].content#</cfoutput>
></cflock>
>
>Note that if someone types in a DocumentID into the url that is not in the
>array an error will be thrown, you need to catch that error. Also do not
>use this technique to store large amounts of data, because your server could
>run out of RAM.
>
>
>++++++++++++++++++++++++++++++++++++++++++
>Pete Freitag ([EMAIL PROTECTED])
>CFDEV.COM
>ColdFusion Developer Resources
>http://www.cfdev.com/
>
>
>-----Original Message-----
>From: Gonzo Rock [mailto:[EMAIL PROTECTED]]
>Sent: Friday, August 31, 2001 3:36 PM
>To: CF-Talk
>Subject: RE: Efficient Query Manipulation?
>
>
>Bryan...
>
>Love that you responded... I was beginning to feel invisible on this list
>;-)
>
>Ummmmmm... Ok You say the DBServer should absorb the load, not the CFServer.
>
>So Refinding 100 indexed database records is faster/easier/MoreResource
>Efficient than CFServer manipulating 100 records stored in an Array. Very
>Interesting point.
>
>RE the interface:
>
>Thanks for the ideas... not sure what I'll be doing... Currently I have
>three submit buttons for each Row now... insert above this row, delete this
>row, edit this row. Just want to work out the best way to do this before
>going on because it will be central and used heavily in the rest of this
>application.
>
>again, thanks for making me not feel so invisible ;)
>Gonzo
>
>
>
>
>At 12:17 PM 8/31/01 -0700, you wrote:
>>It is not very efficient to convert query results to an array. The
>overhead
>>involved is completely avoidable. More often than not the database machine
>>will be more powerful (and reliable) than the CF server. When you are
>faced
>>with a decision between loading up the DB machine or the CF machine I would
>>choose the DB machine every time.
>>
>>You may also want to modify the interface...
>>
>>Place a checkbox next to each row containing that row's ID and have
>multiple
>>submit buttons at the bottom such as "Delete All Checked Rows", and "Move
>>Checked Rows Up", and "Move Checked Rows Down". This way you can modify
>>many rows with one query and you don't have to reload the page more than
>>once. You would need to put a little thought into the process in order to
>>maintain an un-broken sequence (i.e. how to avoid a gap between 5 and 7
>when
>>deleting 6) and so on...
>>
>>
>>Bryan Love ACP
>>Internet Application Developer
>>Telecommunication Systems Inc.
>>[EMAIL PROTECTED]
>>
>>
>>
>>-----Original Message-----
>>From: Gonzo Rock [mailto:[EMAIL PROTECTED]]
>>Sent: Friday, August 31, 2001 10:23 AM
>>To: CF-Talk
>>Subject: Efficient Query Manipulation?
>>
>>
>>I am rather new at CF and am trying to decide how to go about manipulating
>>sets of records in a database.
>>
>>1)Use cached queries
>>-- OR --
>>2)Build an array.
>>
>>My dilemma goes like this...
>>
>>- A user Queries the database and gets a set of say 50 to 100 records in a
>>list. On of the fields retrieved is the SEQUENCE of the record in the list.
>>- Next the user both inserts new items into and deletes current items from
>>this list until they are satisfied with the contents of the list.
>>
>>
>>
>>I can update the database on each insert or deletion, modifying many
>records
>>to update the SEQUENCE value of the records. (An obvious Downside is lots
>of
>>database activity)
>>
>>-- OR --
>>
>>My most current thinking is that stuffing the Query into an Array would be
>a
>>good idea... Then I could manipulate the Array, inserting and deleting rows
>>until a time where the user would commit the Array. (An obvious Downside is
>>loss of all work done in the session if the App/OrSomethingElse crashes.)
>>
>>Is this an acceptable practice?
>>
>>Are there techniques?
>>
>>What's the view from the Brainiacs on this list?
>>
>
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