As of ColdFusion 4.5, ColdFusion Administrator settings are cached to improve performance. This is a good thing, unless you ever manipulated the Administrator settings directly (as my tag does). If you do manipulate these settings you'll need to force ColdFusion to reread the settings using the...
CLIENT and SESSION variables are different. SESSION variables supports complex data types (like arrays and structures), but they are limited to a single machine. CLIENT variables can be shared in a clustered environment, but they do not support complex data types. So how do you get the best of both...
Any time you perform an assignment or pass an attribute in ColdFusion you use NAME=VALUE pairs. ColdFusion allows spaces before or after the = sign, but other languages (most notably XML) do not. While there is nothing wrong with having spaces before or after the equals sign, it's best to get used...
ColdFusion lists are simple to use, but they are not as fast as arrays. In fact, array access is as much as three times faster than list access. So, while lists are simple to use, don't overuse them. (Applies to: ColdFusion 2 (or later))
When you define your data sources for use with ColdFusion, don't ever use the database administrator's login ("sa" on SQL Server for example). With administrative access you greatly increase the chance of someone executing rogue SQL statements (like DROP table). Give the data source just the access...
Never ever assume that a variable exists, even if you wrote the code that passes that variable (perhaps as a URL parameter or a FORM field). To be safe, use a list of tags to initialize all variables. If they do indeed exist the tag will be ignored, so no downside, and lots of upside. (Applies to:...
All SQL implementations have reserved words, words that have special meaning to the database engine. Be very careful to respect these reserved words or your app will start doing funny things when you least expect it. This includes the word "date" which must never ever be used as a column name....
Need to know the names of the columns retrieved in a database query? Simply refer to #QUERY.ColumnList# (replacing QUERY with your own query name). (Applies to: ColdFusion 3 (or later))
Any time you use a ColdFusion variable within a SQL statement, pass it with . This tag improves performance and also helps secure your SQL from potential URL tampering. (Applies to: ColdFusion 4.5 (or later))
ColdFusion Custom Tags often have to return results back to the calling code. Resist the temptation to hardcode the names of the variables that will contain these results. Instead, let the caller specify the desired variable name as a tag attribute. (Applies to: ColdFusion 3 (or later))