What is the difference between and ? From a functional perspective nothing at all - IsDefined() returns YES or NO (or TRUE or FALSE) and if you don't specify what it is your are comparing against then ColdFusion treats it as if you are checking for TRUE. But from a performance perspective there is...
ColdFusion provides a Web based interface (in the ColdFusion Administrator) for creating and configuring ODBC data sources, but not all ODBC drivers are supported this way. ColdFusion can use any drivers, even those not supported directly via the Web interface. To use other drivers simply create...
ColdFusion Studio (and HomeSite) include extensive help documents that may be browsed and searched. In addition, you can add help content yourself (either your own or downloaded from the Web). All you need to do is drop the files (HTML files and supporting images if needed) into a subdirectory...
Many ColdFusion tags take server names as attributes - for example, (directly or via the ColdFusion Administrator), , , , and . Every time ColdFusion processes a server name you are forcing a DNS lookup to occur - and while DNS information is cached, eliminating DNS lookups can save precious time....
Want to force a refresh of all database connections at once? You can as of ColdFusion 4.5. In the ColdFusion Administrator select the "Verify Data Sources" screen - you'll see a button marked Release there which you can click to release all data source connections which will force a complete...
The SQL UPDATE and DELETE statements take WHERE clauses to restrict the data being updated or deleted. Failing to provide a WHERE clause causes the update or deletion of all rows in a table, and providing an incorrect WHERE clause could cause the updating and deleting of the wrong rows in a table....
The ColdFusion default page timeout value is specified in the ColdFusion Administrator. But that value can be overridden for specific pages using the "RequestTimeout" parameter which allows you to specify a timeout value in seconds. To do this, simply append RequestTimeout=value to the URL (just...
Data retrieved from a database is usually returned (to ColdFusion and any other database client) one row at a time. You can control the number of rows sent per request using the tag's BLOCKFACTOR attribute - the default is 1 and you can specify any number from 1 to 100. For example, if you retrieve...
Ever named a form field something like "order_date"? Don't. ColdFusion looks for specific field name suffixes to tell it to perform validation, and _date is one of those. Others to avoid are _eurodate, _integer, _float, _range, and _time. If your database column is named this way you'll...
The names of any database related entities (like databases, tables, columns, view, stored procedures) should be plain text and not contain any spaces or special characters (for example, hyphens and periods). Using these characters will create endless difficulties for client applications (like...