MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX, Develop Manual

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Building ColdFusion components 235
Using the GetMetaData function
The CFML
GetMetaData
function returns a structure containing all the metadata of a CFC
instance. This structure contains substantially more data about the CFC than
cfdump
shows, and
includes the following information:
•
All attributes to the component tag, including any metadata-only attributes, plus the
component path.
•
An array of structures containing full information on each method (function) in the
component. This information includes all attributes, including metadata-only function and
parameter attributes.
•
Within each function structure, a Parameters element containing an array of parameters
specified by
cfargument
tags. Information on each parameter includes any metadata-only
attributes.
•
Information about any properties that are specified using the
cfproperty
tag
For information on how to specify CFC metadata, including how to use component tags and how
to specify metadata-only attributes, see
“Documenting CFCs” on page 240 .
Building ColdFusion components
You use the
cfcomponent
and
cffunction
tags to create ColdFusion components. By itself, the
cfcomponent
tag does not provide functionality. Rather, the
cfcomponent
tag provides an
envelope that describes the functionality that you build in CFML and enclose in
cffunction
tags.
The following example creates a component with two methods:
<cfcomponent>
<cffunction name="getEmp">
<cfquery name="empQuery" datasource="ExampleApps" dbtype="ODBC" >
SELECT FIRSTNAME, LASTNAME, EMAIL
FROM
tblEmployees
</cfquery>
<cfreturn empQuery>
</cffunction>
<cffunction name="getDept">
<cfquery name="deptQuery" datasource="ExampleApps" dbtype="ODBC" >
SELECT
*
FROM tblDepartments
</cfquery>
<cfreturn deptQuery>
</cffunction>
</cfcomponent>
In the example, two
cffunction
tags define two component methods,
getEmp
and
getDept
.
When invoked, the component methods query the ExampleApps database. The
cfreturn
tag
returns the query results to the client.
The following sections discuss how you define components and their methods.