RE: evaluate

[Daniel Elmore]

Application variables is better for cpu time, but using evaluate is better for server RAM. J   From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kevin Fricke Sent: Tuesday, December 21, 2004 12:11 PM To: list@dfwcfug.org Subject: RE: evaluate   Last question regarding evaluate....   What would be better (for the server and processing time)....setting application variables in the Application.cfm page or using the evaluate command?   Kevin -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Daniel Elmore Sent: Saturday, December 18, 2004 11:36 AM To: list@dfwcfug.org Subject: RE: evaluate 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: <cfoutput query="#cityname#_get_query">   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: <cfoutput query="#recordset1#">   You just have to do this: <cfoutput query="recordset1">   When using cfdump you will need the evaluate: <cfdump var="#evaluate('#cityname#'_get_query')#">   Because cfdump doesn't want the variable name, but a reference to the data itself. Which is why you have to do this: <cfdump var="#recordset1#">   Instead of this: <cfdump var="recordset1">   When outputting data you will need evaluate. <cfoutput> 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: <cfoutput> Recordset1.column1[1] </cfoutput>   It obviously goes like this: <cfoutput> #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: list@dfwcfug.org 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: list@dfwcfug.org 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 list@dfwcfug.org To unsubscribe:    http://www.dfwcfug.org/form_MemberUnsubscribe.cfm To subscribe:    http://www.dfwcfug.org/form_MemberRegistration.cfm       ---------------------------------------------------------- To post, send email to list@dfwcfug.org To unsubscribe:    http://www.dfwcfug.org/form_MemberUnsubscribe.cfm To subscribe:    http://www.dfwcfug.org/form_MemberRegistration.cfm     ---------------------------------------------------------- To post, send email to list@dfwcfug.org To unsubscribe:    http://www.dfwcfug.org/form_MemberUnsubscribe.cfm To subscribe:    http://www.dfwcfug.org/form_MemberRegistration.cfm