Passes queries or SQL statements to a data source.

Macromedia recommends that you use the cfqueryparam tag within every cfquery tag, to help secure your databases from unauthorized users. For more information, see Security Bulletin ASB99-04, "Multiple SQL Statements in Dynamic Queries," in the Macromedia Security Zone, www.macromedia.com/devnet/security/security_zone/asb99-04.html, and Chapter 20, "Accessing and Retrieving Data" in ColdFusion MX Developer's Guide.

Database manipulation tags

cfinsert, cfprocparam, cfprocresult, cfqueryparam, cfstoredproc, cftransaction, cfupdate; "Optimizing database use" in Chapter 13, "Designing and Optimizing a ColdFusion Application," and Chapters 19-22 in ColdFusion MX Developer's Guide

ColdFusion MX 7:

• Added the result attribute for specifying an alternate name for the structure that holds the result variables.
• Added result variables for the SQL statement executed (sql), the number of records returned (recordcount), whether the query was cached (cached), an array of cfqueryparam values (sqlparameters), and the list of columns in the returned query (columnlist).

ColdFusion MX:

• Changed Query of Queries behavior: it now supports a larger subset of standard SQL.
• Changed dot notation support: ColdFusion now supports dot notation within a record set name. ColdFusion interprets such a name as a structure.
• Deprecated the connectString, dbName, dbServer, provider, providerDSN, and sql attributes, and all values of the dbtype attribute except query. They do not work, and might cause an error, in releases later than ColdFusion 5.
• New query object variable: cfquery.ExecutionTime.
• No longer supports native drivers. It now uses JDBC (and ODBC-JDBC bridge) for database connectivity.

Use this tag to execute a SQL statement against a ColdFusion data source. Although you can use the cfquery tag to execute any SQL Data Definition Language (DDL) or Data Manipulation Language (DML) statement, you typically use it to execute a SQL SELECT statement.

This tag creates a query object, providing this information in query variables:

query_name.currentRow

query_name.columnList

query_name.RecordCount

The cfquery tag also returns the following result variables in a structure. You can access these variables with a prefix of the name you specified in the result attribute. For example, if you assign the name myResult to the result attribute, you would retrieve the name of the SQL statement that was executed by accessing #myResult.sql#. The result attribute provides a way for functions or CFCs that are called from multiple pages, possibly at the same time, to avoid overwriting results of one call with another.

result_name.sql

result_name.recordcount

result_name.cached

result_name.sqlparameters

result_name.columnList

result_name.ExecutionTime

You can cache query results and execute stored procedures. For information about this and about displaying cfquery output, see ColdFusion MX Developer's Guide.

Because the timeout attribute only affects the maximum time for each suboperation of a query, the cumulative time may exceed its value. To set a timeout for a page that might get a very large result set, set the Administrator > Server Settings > Timeout Requests option to an appropriate value or use the RequestTimeout attribute of the cfsetting tag (for example, <cfsetting requestTimeout="300">).

The Caching page of the ColdFusion MX Administrator specifies the maximum number of cached queries. Setting this value to 0 disables query caching.

You cannot use ColdFusion reserved words as query names.

You cannot use SQL reserved words as variable or column names in a Query of Queries, unless they are escaped. The escape character is the bracket []; for example:

SELECT [count] FROM MYTABLE. 

For a list of reserved keywords in ColdFusion MX, see "Escaping reserved keywords" in Chapter 22, "Using Query of Queries" in ColdFusion MX Developer's Guide.

<!--- This example shows the use of CreateTimeSpan with CFQUERY ------>
<!--- to cache a record set. Define startrow and maxrows to ---->
<!--- facilitate 'next N' style browsing. ---->
<cfparam name="MaxRows" default="10">
<cfparam name="StartRow" default="1">
<!--------------------------------------------------------------------
Query database for information if cached database information has
not been updated in the last six hours; otherwise, use cached data.
--------------------------------------------------------------------->
<cfquery 
name="GetParks" datasource="cfdocexamples" 
cachedwithin="#CreateTimeSpan(0, 6, 0, 0)#">
SELECT PARKNAME, REGION, STATE
FROM Parks
ORDER BY ParkName, State
</cfquery>
<!--- Build HTML table to display query. ------------------------->
<table cellpadding="1" cellspacing="1">
   <tr>
      <td bgcolor="f0f0f0">
         &nbsp;
      </td>
      <td bgcolor="f0f0f0">
         <b><i>Park Name</i></b>
      </td>
      <td bgcolor="f0f0f0">
         <b><i>Region</i></b>
      </td>
      <td bgcolor="f0f0f0">
         <b><i>State</i></b>
      </td>
   </tr>
<!--- Output the query and define the startrow and maxrows parameters. 
Use the query variable CurrentCount to keep track of the row you 
are displaying. ------>
<cfoutput query="GetParks" startrow="#StartRow#" maxrows="#MaxRows#">
   <tr>
      <td valign="top" bgcolor="ffffed">
         <b>#GetParks.CurrentRow#</b>
      </td>
      <td valign="top">
         <font size="-1">#ParkName#</font>
      </td>
      <td valign="top">
         <font size="-1">#Region#</font>
      </td>
      <td valign="top">
         <font size="-1">#State#</font>
      </td>
   </tr>
</cfoutput>
<!--- If the total number of records is less than or equal
to the total number of rows, then offer a link to
the same page, with the startrow value incremented by
maxrows (in the case of this example, incremented by 10). --------->
   <tr>
      <td colspan="4">
      <cfif (StartRow + MaxRows) LTE GetParks.RecordCount>
         <cfoutput><a href="#CGI.SCRIPT_NAME#?startrow=#Evaluate(StartRow + 
MaxRows)#">
         See next #MaxRows# rows</a></cfoutput> 
      </cfif>
      </td>
   </tr>
</table>