RE: evaluate

Daniel Elmore Sat, 18 Dec 2004 10:18:39 -0800

Hi Kevin, with that situation you don't need the evaluate most of the time. When working with dynamic variable names you need evaluate when your doing 2 things.

1. Generating the variable from other variables and constants.

2. Then pointing to the data that the variable represents.

Your doing #1 but it looks like most of the time your not going doing #2. Here are some examples.

When using cfoutput or cfloop you can just use:

This works because all you need to do is generate the string name of the query, you don't need to reference the query directly, the cfoutput tag does that for you. That is why you don't have to do this:

You just have to do this:

When using cfdump you will need the evaluate:

Because cfdump doesn't want the variable name, but a reference to the data itself. Which is why you have to do this:

Instead of this:

When outputting data you will need evaluate.

First row of first column: #evaluate("#cityname#_get_query.column1[1]")#

</cfoutput>

This is because once again you need to do #1 and #2. Hints this won't work:

Recordset1.column1[1]

</cfoutput>

It obviously goes like this:

#recordset1.column1[1]#

</cfoutput>

If you need to do this frequently. It might be worth to build an alternate structure for the data. If you placed some of the data in a struct of structs you could use syntax like this:

get_query[“#cityname#”][column_name][row_number]

It’s a way to dynamically select the variable without using the evaluate. You would have to create a custom loop to populate the structs for your querys. But if you save it in the application scope it will be minimum overhead and you can avoid using the evaluate function for outputting data.

Hope that helps

Daniel Elmore

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kevin Fricke
Sent: Friday, December 17, 2004 10:08 PM
To: [EMAIL PROTECTED]
Subject: RE: evaluate

Daniel,

I am using the evaluate command to determine which query to pull data from.

The reason for this is there are multiple queries for different cities and I

would like to cache the query. The sites for the different cities pull the

data from the query based upon the city name in the application page. For

example, we have a site for Austin, which uses query "austin_get_query" and

a site for Dallas which uses "dallas_get_query". In the application page

for each city I have a variable for cityName, therefore, I am using

#evaluate(cityName & '_get_query')#. Do you recommend another way?

Thanks for the advise!

Kevin

-----Original Message-----

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]

Behalf Of Daniel Elmore

Sent: Friday, December 17, 2004 5:01 PM

To: [EMAIL PROTECTED]

Subject: RE: evaluate

The evaluate function is processor intensive. You should avoid it whenever

possible. However, in some situation it is necessary and then you should use

it and not feel guilty. It takes a good understanding of CF syntax to know

when it is necessary.

-----Original Message-----

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf

Of Kevin Fricke

Sent: Friday, December 17, 2004 3:28 PM

To: CFLIST

Subject: evaluate

Is there any reason to avoid using the evaluate command? Does it slow down

processing?

Thanks,

kevin

----------------------------------------------------------

To post, send email to [EMAIL PROTECTED]

To unsubscribe:

http://www.dfwcfug.org/form_MemberUnsubscribe.cfm

To subscribe:

http://www.dfwcfug.org/form_MemberRegistration.cfm

----------------------------------------------------------

To post, send email to [EMAIL PROTECTED]

To unsubscribe:

http://www.dfwcfug.org/form_MemberUnsubscribe.cfm

To subscribe:

http://www.dfwcfug.org/form_MemberRegistration.cfm

----------------------------------------------------------

To post, send email to [EMAIL PROTECTED]

To unsubscribe:

http://www.dfwcfug.org/form_MemberUnsubscribe.cfm

To subscribe:

http://www.dfwcfug.org/form_MemberRegistration.cfm

RE: evaluate

Reply via email to