.. _Modify_EnableSHACLConstraintsForThisClass:

Modify > Enable SHACL constraints for this class
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This feature is available from the :ref:`ModifyMenu` of classes in an Ontology asset collection,
where the classes are not (yet) also node shapes.
The feature opens a dialog allowing you to add a statement that declares the class to be also
a node shape, making it available to various important features of TopBraid, in particular editing.

As some background, TopBraid is based on SHACL to learn about the properties that apply to
instances of the classes from an ontology.
In SHACL, it is a common practice to declare classes to also be instance of ``sh:NodeShape``.
Doing so instructs the SHACL engines that all property declarations and constraints attached to the
class will apply to all instances of that class.
This is an alternative to having separate node shapes and a *target class* statement.

.. tip::
   Use this feature after you have imported an ontology that was not defined using SHACL, for example
   pure RDF Schema or OWL ontologies.


**Further Reading on SHACL**

* `Form Generation using SHACL and DASH (External Link) <https://datashapes.org/forms.html>`_
* `SHACL Advanced Features Specification (External Link) <https://w3c.github.io/shacl/shacl-af/>`_
* `SHACL W3C Specification (External Link) <https://www.w3.org/TR/shacl/>`_

**Further Reading on Ontologies**

* :ref:`working_with_ontologies_target`

**Further Reading on Modify Menu**

* :ref:`scripting_actions`

**Further Reading on TopBraid**

* :ref:`introduction`