Query of Queries is based on manipulating the recordset, which you can create using the cfquery tag and other ways.
When you execute a database query, Adobe ColdFusion retrieves the data in a recordset. In addition to presenting recordset data to the user, you can manipulate this recordset to improve the performance of your application.
Because a recordset contains rows (records) and columns (fields), you can think of it as a virtual database table, or as a spreadsheet. For example, the cfpop tag retrieves a recordset in which each row is a message and each column is a message component, such as To, From, and Subject.
Creating a recordset
You can perform a Query of Queries on any ColdFusion tag or function that generates a recordset, including the following:
- cfcollection
- cfdirectory
- cfftp
- cfhttp
- cfindex
- cfldap
- cfmail
- cfpop
- cfprocresult
- cfquery(against a database or against another Query of Queries)
- cfsearch
- cfstoredproc
- cfwddx
- The QueryNew function
Creating a recordset with the QueryNew() function
In addition to creating a recordset by using a cfquery or other CFML tags, you can create it with the QueryNew function.
Create a ColdFusion page with the following content:
<html>
<head>
<title>The queryNew function</title>
</head>
<body>
<h2>QueryNew Example</h2>
<!--- Create a query, specify data types for each column. --->
<cfset qInstruments = queryNew("name, instrument, years_playing",
"CF_SQL_VARCHAR, CF_SQL_VARCHAR, CF_SQL_INTEGER")>
<!--- Add rows. --->
<cfset newrow = queryaddrow(qInstruments, 3)>
<!--- Set values in cells. --->
<cfset temp = querysetcell(qInstruments, "name", "Thor", 1)>
<cfset temp = querysetcell(qInstruments, "instrument", "hammer", 1)>
<cfset temp = querysetcell(qInstruments, "years_playing", "1000", 1)>
<cfset temp = querysetcell(qInstruments, "name", "Bjorn", 2)>
<cfset temp = querysetcell(qInstruments, "instrument", "sitar", 2)>
<cfset temp = querysetcell(qInstruments, "years_playing", "24", 2)>
<cfset temp = querysetcell(qInstruments, "name", "Raoul", 3)>
<cfset temp = querysetcell(qInstruments, "instrument", "flute", 3)>
<cfset temp = querysetcell(qInstruments, "years_playing", "12", 3)>
<!--- Output the query. --->
<cfoutput query="qInstruments">
<pre>#name# #instrument# #years_playing#</pre>
</cfoutput>
<h3>Individual record retrieval:</h3>
<cfoutput>
<p>#qInstruments.name[2]# has played #qInstruments.instrument[2]# for
#qInstruments.years_playing[2]# years.</p>
</cfoutput>
</body>
</html>- Save the page as queryNew.cfm in the myapps directory under the web_root directory.
- Display queryNew.cfm in your browser
