
About Query of Queries
461
The first
cfdump
tag shows the master query, which retrieves all records. The second
cfdump
shows the Query of Queries results.
Tip:
Adjust the score criterion of the detail query to reflect the contents of your collection.
The next example shows how a Query of Queries combines record sets from a
cfdirectory
tag,
which is limited to retrieval of one file type per use.
To use Query of Queries to combine record sets:
1
Create a ColdFusion page with the following content:
<html>
<head>
<title>Images Folder</title>
</head>
<body>
<h2>Image Retrieval with QoQ</h2>
<!--- set the images directory --->
<cfset dir = ("C:\pix\")>
<!--- retrieve all GIFs --->
<cfdirectory name="GetGIF"
action="list"
directory="#dir#"
filter="*.gif">
<!--- retrieve all JPGs --->
<cfdirectory name="GetJPG"
action="list"
directory="#dir#"
filter="*.jpg">
<!--- join the queries with a UNION in a QoQ (cfdirectory
automatically returns the directory name as "Name") --->
<cfquery dbtype="query" name="GetBoth">
SELECT * FROM GetGIF
UNION
SELECT * FROM GetJPG
ORDER BY Name
</cfquery>
<!--- display output in a linked, ordered list --->
<cfoutput>
<p>The <strong>#dir#</strong> directory contains #GetBoth.RecordCount#
images:<br>
<ol>
<cfloop query="GetBoth">
<li><a href="../images/#Name#">#GetBoth.Name#</a><br>
</cfloop>
</ol>
</cfoutput>
</body>
</html>
2
Save the page as qoq_cfdirectory.cfm in the myapps directory under the
web_root
.
3
In your web browser, enter the following URL to display the query results:
http://127.0.0.1/myapps/qoq_cfdirectory.cfm
Содержание ColdFusion MX
Страница 1: ...Developing ColdFusion MX Applications...
Страница 22: ...22 Contents...
Страница 38: ......
Страница 52: ...52 Chapter 2 Elements of CFML...
Страница 162: ......
Страница 218: ...218 Chapter 10 Writing and Calling User Defined Functions...
Страница 250: ...250 Chapter 11 Building and Using ColdFusion Components...
Страница 264: ...264 Chapter 12 Building Custom CFXAPI Tags...
Страница 266: ......
Страница 314: ...314 Chapter 14 Handling Errors...
Страница 344: ...344 Chapter 15 Using Persistent Data and Locking...
Страница 349: ...About user security 349...
Страница 357: ...Security scenarios 357...
Страница 370: ...370 Chapter 16 Securing Applications...
Страница 388: ...388 Chapter 17 Developing Globalized Applications...
Страница 408: ...408 Chapter 18 Debugging and Troubleshooting Applications...
Страница 410: ......
Страница 426: ...426 Chapter 19 Introduction to Databases and SQL...
Страница 476: ...476 Chapter 22 Using Query of Queries...
Страница 534: ...534 Chapter 24 Building a Search Interface...
Страница 556: ...556 Chapter 25 Using Verity Search Expressions...
Страница 558: ......
Страница 582: ...582 Chapter 26 Retrieving and Formatting Data...
Страница 668: ......
Страница 734: ...734 Chapter 32 Using Web Services...
Страница 760: ...760 Chapter 33 Integrating J2EE and Java Elements in CFML Applications...
Страница 786: ...786 Chapter 34 Integrating COM and CORBA Objects in CFML Applications...
Страница 788: ......
Страница 806: ...806 Chapter 35 Sending and Receiving E Mail...