How use Namespaces in sapui5?

Someone can help with namespaces in sapui5, please. how to use it how to use it, I'm working with eclipse IDE.

I'm following a tutorial, and use this namespace, as would be the namespace with the structure of my project.

       controllerName="sap.ui.demo.db.controllers.App"

the structure of my proyect is:
databinding(proyectname)

->webcontent(folder)
->controllers(folder)
app.controller.js

->databinding(folder)
data.controller.js
data.view.xml

index.html

I tried several ways and I have not been successful.

Solution

The namespaces are set in index.html while bootstrapping. The property used to set is : data-sap-ui-resourceroots. For example :

data-sap-ui-resourceroots='{
            "sap.ui.demo.cart" : "./"
        }'

The above code sets the namespace and from now on 'sap.ui.demo.cart' will point to the folder where my index.html is present ( since I set the property to current folder (./) ). So for your case:

data-sap-ui-resourceroots='{
                "sap.ui.demo.db" : "./"
            }'

Complete bootstrap :

<script
        id='sap-ui-bootstrap'
        src='resources/sap-ui-core.js'
        data-sap-ui-theme='sap_bluecrystal'
        data-sap-ui-libs='sap.m'
        data-sap-ui-compatVersion="edge"
        data-sap-ui-resourceroots='{
            "sap.ui.demo.db" : "./"
        }' >
    </script>