Model representing a PostgreSQL extension.
:param ext_name: Name of the extension to be created, checked or dropped. :type ext_name: str :param ext_version: Optional version of the extension to be created or checked. :type ext_version: str | None :param schema_name: Optional schema name where the extension should be created or checked. :type schema_name: str | None :param cascade: Whether to automatically install the extension dependencies or drop the objects that depend on the extension. :type cascade: bool
