You use the <mx:Model> tag to declare a data model in MXML. An <mx:Model> tag is compiled into a tree of ActionScript objects; the leaves of the tree are scalar values.
MXML Syntax
You can place an <mx:Model> tag in a Flex application file, or in an MXML component file. The tag must have an id value. It cannot be the root tag of an MXML component. The <mx:Model> tag has the following syntax:
<mx:Model id="modelID">
model declaration
</mx:Model>
or:
<mx:Model id="modelID" source="fileName" />
where source specifies an external source, such as a file, for the data model.
The external source can contain static data and data binding expressions.
The file referenced in a source property resides on the server and not on the client machine.
The compiler reads the source value and compiles the source into the application;
the source value is not read at runtime.
The model declaration, either in-line in the tag or in the source file, must have a single root
node that contains all other nodes. You can use MXML binding expressions, such as
{myForm.lastName.text} in the model declaration.
This way you can bind the contents of form fields to a structured data representation.
In the following example, the myEmployee model is placed in an MXML application file:
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
...
<mx:Model id="MyEmployee">
<root>
<name>
<first>Will</first>
<last>Tuckerman</last>
</name>
<department>Accounting</department>
<email>wtuckerman@wilsoncompany.com</email>
</root>
</mx:Model>
...
</mx:Application>