Fixed #326. Added 'form_optional_types'

flask_admin/contrib/sqla/form.py

@@ -196,7 +196,9 @@ class AdminModelConverter(ModelConverterBase):
                                                        model,
                                                        column))
 
-                if not column.nullable and not isinstance(column.type, Boolean):
+                optional_types = getattr(self.view, 'form_optional_types', (Boolean,))
+
+                if not column.nullable and not isinstance(column.type, optional_types):
                     kwargs['validators'].append(validators.InputRequired())
 
                 # Apply label and description if it isn't inline form field

flask_admin/contrib/sqla/view.py

@@ -3,7 +3,7 @@ import logging
 from sqlalchemy.orm.attributes import InstrumentedAttribute
 from sqlalchemy.orm import joinedload
 from sqlalchemy.sql.expression import desc
-from sqlalchemy import or_, Column, func
+from sqlalchemy import Column, Boolean, func, or_
 
 from flask import flash
 
@@ -230,6 +230,16 @@ class ModelView(BaseModelView):
                 ]
     """
 
+    form_optional_types = (Boolean,)
+    """
+        List of field types that should be optional if column is not nullable.
+
+        Example::
+
+            class MyModelView(BaseModelView):
+                form_optional_types = (Boolean, Unicode)
+    """
+
     def __init__(self, model, session,
                  name=None, category=None, endpoint=None, url=None):
         """