Hello.
I’m a Yii newbie and I’m trying to work with modules and submodules. However, there is so little documentation on them and its a pain, really.
I’d appreciate if anyone can point me towards resources on them.
Also, how does one declare a submodule for an existing module?
Secondly, how do I create controllers in a submodule using Gii?
Thanks in advance
Hi Odun
Welcome to the world of Yii 
The Yii tutorial answers most of your questions on modules and sub modules. The comments that appear below the tutorial are really helpful as well. The Module documentation is always a good point of reference as you go along.
To declare a sub module, in your config.php, you would have something like so:
return array(
......
'modules'=>array(
'modulename'=>array(
'modules'=>array(
'submodulename',
),
),
),
....
);
Once the sub module has been declared, in the Gii controller generator, give the controllerid as <modulename>/<submodulename>/<controllername>
Hope that helps.
A simple tutorial:
In this example, you want to create a module core with a submodule management in the website.
Create with gii the two modules. Add the folder "modules" in the module core . Remove the module management in this new folder.
The File-Structure should be a kind of this:
/protected
---/modules
---/core
---/controllers
---/modules
---/management
--- ...
---/views
Now, You must configure your main.php or config.php in the folder "config" ( in the root-folder "protected"):
'modules'=>array(
// uncomment the following to enable the Gii tool
'gii' => array(
'class' => 'system.gii.GiiModule',
'generatorPaths' => array(
'bootstrap.gii', // since 0.9.1 /Twitter bootstrap)
),
),
'core'=>array(
'modules'=>array(
'management',
),
),
),
And modify the "import"-Array in this file:
// [MODULE] Core
'application.modules.core.models.*',
'application.modules.core.components.*',
'application.modules.core.widgets.*',
// [MODULE] Management
'application.modules.core.modules.management.models.*',
'application.modules.core.modules.management.components.*',
Now, you have the possibility to use all components, models, etc. of the submodule "management" in the same kind like the module core.
For example, if you want to add a submodule login in submodule management, you have to modify your "modules"-Array like that:
'core'=>array(
'modules'=>array(
'management' => array(
'modules' => array(
'login',
),
),
),
),
),
You have to modify your "import"-Array too.
And so on, and so on.
I hope, that can help you.
Best Regards,
Riff