User Guide

Linking Dynamically from Graphs 77

Linking Dynamically from Graphs

You can make Flash-format bar and pie charts interactive so that ColdFusion

displays a new data point–specific Web page when the user clicks a bar or pie wedge.

ColdFusion provides two methods for specifying the destination page:

• For data points from queries, ColdFusion takes the value of the

cfgraph URL

attribute, appends the value of the query column specified by the

URLColumn

attribute, and sends the resulting Web request.

• For data points from

cfgraphdata tags, ColdFusion uses the value of the tag’s

URL attribute as the page to link to.

Using ColdFusion you can combine a static URL component with a query column

component. This lets you link dynamically based on query column data without

having to format the column contents as a URL. For example, you can use the values

of the Dept_Name field in the CompanyInfo database to determine the data to

display. To do this, follow these guidelines:

• In the cfgraph tag, specify a single Web page in the URL attribute.

• In the URL attribute, include the name of a parameter, but not its value, in the

form ParameterName

• In the URLColumn attribute, specify a query column that contains the value of the

parameter being passed.

• In the target page, determine the data to be displayed based on the parameter

that gets passed.

The example code in the following procedure illustrates this technique.

Example: dynamically linking from a pie chart

In the following example, when you click a pie wedge, ColdFusion displays a table

containing the detailed salary information for the departments represented by the

wedge. The example is divided into two parts: creating the detail page and making

the graph dynamic.

Part 1: Creating the detail page

1 Create a new application page in ColdFusion Studio.

This page displays the drill-down information on the selected department based

on the department name passed as the URL parameter.

2 Edit the page so that it appears as follows:

SELECT Departmt.Dept_Name,

Employee.FirstName,

Employee.LastName,

Employee.StartDate,

Employee.Salary,

Employee.Contract

FROM Departmt, Employee

WHERE Departmt.Dept_Name = ’#URL.Dept_Name#’

AND Departmt.Dept_ID = Employee.Dept_ID