Check data before category

Change-Id: I7e523a08fcfd3f9ea322a399c71637f268cbb38e
Signed-off-by: ReemMahmoud <rfawzy.ext@orange.com>

13 files changed, 437 insertions, 27 deletions

diff --git a/python_moondb/Changelog b/python_moondb/Changelog
index 19cd0ac0..acd72883 100644
--- a/python_moondb/Changelog
+++ b/python_moondb/Changelog
@@ -69,3 +69,7 @@ CHANGES
 1.2.8
 -----
 - Add unique constraints on db tables
+
+1.2.9
+-----
+- Add some verifications when deleting some elements in database
diff --git a/python_moondb/python_moondb/__init__.py b/python_moondb/python_moondb/__init__.py
index b266a9d4..287558f7 100644
--- a/python_moondb/python_moondb/__init__.py
+++ b/python_moondb/python_moondb/__init__.py
@@ -3,5 +3,5 @@
 # license which can be found in the file 'LICENSE' in this package distribution
 # or at 'http://www.apache.org/licenses/LICENSE-2.0'.
 
-__version__ = "1.2.8"
+__version__ = "1.2.9"
 
diff --git a/python_moondb/python_moondb/api/model.py b/python_moondb/python_moondb/api/model.py
index 57857cd2..f5858662 100644
--- a/python_moondb/python_moondb/api/model.py
+++ b/python_moondb/python_moondb/api/model.py
@@ -9,7 +9,6 @@ from python_moonutilities import exceptions
 from python_moonutilities.security_functions import filter_input, enforce
 from python_moondb.api.managers import Managers
 
-
 logger = logging.getLogger("moon.db.api.model")
 
 
@@ -30,6 +29,10 @@ class ModelManager(Managers):
         if model_id not in self.driver.get_models(model_id=model_id):
             raise exceptions.ModelUnknown
         # TODO (asteroide): check that no policy is connected to this model
+        policies = Managers.PolicyManager.get_policies(user_id=user_id)
+        for policy in policies:
+            if policies[policy]['model_id'] == model_id:
+                raise exceptions.DeleteModelWithPolicy
         return self.driver.delete_model(model_id=model_id)
 
     @enforce(("read", "write"), "models")
@@ -65,6 +68,10 @@ class ModelManager(Managers):
         if meta_rule_id not in self.driver.get_meta_rules(meta_rule_id=meta_rule_id):
             raise exceptions.MetaRuleUnknown
         # TODO (asteroide): check and/or delete data and assignments and rules linked to that meta_rule
+        models = self.get_models(user_id=user_id)
+        for model_id in models:
+            if models[model_id]['meta_rules'] == meta_rule_id:
+                raise exceptions.DeleteMetaRuleWithModel
         return self.driver.delete_meta_rule(meta_rule_id=meta_rule_id)
 
     @enforce("read", "meta_data")
@@ -83,6 +90,13 @@ class ModelManager(Managers):
         # TODO (asteroide): delete all meta_rules linked to that category
         if category_id not in self.driver.get_subject_categories(category_id=category_id):
             raise exceptions.SubjectCategoryUnknown
+        meta_rules = self.get_meta_rules(user_id=user_id)
+        for meta_rule_id in meta_rules:
+            for subject_category_id in meta_rules[meta_rule_id]['subject_categories']:
+                if subject_category_id == category_id:
+                    raise exceptions.DeleteCategoryWithMetaRule
+        if self.driver.is_subject_data_exist(category_id=category_id):
+            raise exceptions.DeleteCategoryWithData
         return self.driver.delete_subject_category(category_id=category_id)
 
     @enforce("read", "meta_data")
@@ -101,6 +115,13 @@ class ModelManager(Managers):
         # TODO (asteroide): delete all meta_rules linked to that category
         if category_id not in self.driver.get_object_categories(category_id=category_id):
             raise exceptions.ObjectCategoryUnknown
+        meta_rules = self.get_meta_rules(user_id=user_id)
+        for meta_rule_id in meta_rules:
+            for object_category_id in meta_rules[meta_rule_id]['object_categories']:
+                if object_category_id == category_id:
+                    raise exceptions.DeleteCategoryWithMetaRule
+        if self.driver.is_object_data_exist(category_id=category_id):
+            raise exceptions.DeleteCategoryWithData
         return self.driver.delete_object_category(category_id=category_id)
 
     @enforce("read", "meta_data")
@@ -118,6 +139,12 @@ class ModelManager(Managers):
         # TODO (asteroide): delete all data linked to that category
         # TODO (asteroide): delete all meta_rules linked to that category
         if category_id not in self.driver.get_action_categories(category_id=category_id):
-            raise exceptions.ActionCategoryExisting
+            raise exceptions.ActionCategoryUnknown
+        meta_rules = self.get_meta_rules(user_id=user_id)
+        for meta_rule_id in meta_rules:
+            for action_category_id in meta_rules[meta_rule_id]['action_categories']:
+                if action_category_id == category_id:
+                    raise exceptions.DeleteCategoryWithMetaRule
+        if self.driver.is_action_data_exist(category_id=category_id):
+            raise exceptions.DeleteCategoryWithData
         return self.driver.delete_action_category(category_id=category_id)
-
diff --git a/python_moondb/python_moondb/api/policy.py b/python_moondb/python_moondb/api/policy.py
index 9e7ad96c..69392e6d 100644
--- a/python_moondb/python_moondb/api/policy.py
+++ b/python_moondb/python_moondb/api/policy.py
@@ -8,6 +8,7 @@ import logging
 from python_moonutilities.security_functions import enforce
 from python_moondb.api.managers import Managers
 from python_moonutilities import exceptions
+# from python_moondb.core import PDPManager
 
 logger = logging.getLogger("moon.db.api.policy")
 
@@ -46,6 +47,11 @@ class PolicyManager(Managers):
         # TODO (asteroide): unmap PDP linked to that policy
         if policy_id not in self.driver.get_policies(policy_id=policy_id):
             raise exceptions.PolicyUnknown
+        pdps = self.PDPManager.get_pdp(user_id=user_id)
+        for pdp in pdps:
+            for policy_id in pdps[pdp]['security_pipeline']:
+                if policy_id == policy_id:
+                    raise exceptions.DeletePolicyWithPdp
         return self.driver.delete_policy(policy_id=policy_id)
 
     @enforce(("read", "write"), "policies")
@@ -147,6 +153,9 @@ class PolicyManager(Managers):
     @enforce(("read", "write"), "data")
     def delete_subject_data(self, user_id, policy_id, data_id):
         # TODO (asteroide): check and/or delete assignments linked to that data
+        subject_assignments = self.get_subject_assignments(user_id=user_id, policy_id=policy_id, subject_id=data_id)
+        if subject_assignments:
+            raise exceptions.DeleteData
         return self.driver.delete_subject_data(policy_id=policy_id, data_id=data_id)
 
     @enforce("read", "data")
@@ -175,6 +184,9 @@ class PolicyManager(Managers):
     @enforce(("read", "write"), "data")
     def delete_object_data(self, user_id, policy_id, data_id):
         # TODO (asteroide): check and/or delete assignments linked to that data
+        object_assignments = self.get_object_assignments(user_id=user_id, policy_id=policy_id, object_id=data_id)
+        if object_assignments:
+            raise exceptions.DeleteData
         return self.driver.delete_object_data(policy_id=policy_id, data_id=data_id)
 
     @enforce("read", "data")
@@ -203,6 +215,9 @@ class PolicyManager(Managers):
     @enforce(("read", "write"), "data")
     def delete_action_data(self, user_id, policy_id, data_id):
         # TODO (asteroide): check and/or delete assignments linked to that data
+        action_assignments = self.get_action_assignments(user_id=user_id, policy_id=policy_id, action_id=data_id)
+        if action_assignments:
+            raise exceptions.DeleteData
         return self.driver.delete_action_data(policy_id=policy_id, data_id=data_id)
 
     @enforce("read", "assignments")
diff --git a/python_moondb/python_moondb/backends/sql.py b/python_moondb/python_moondb/backends/sql.py
index a838a854..366ed7de 100644
--- a/python_moondb/python_moondb/backends/sql.py
+++ b/python_moondb/python_moondb/backends/sql.py
@@ -548,6 +548,16 @@ class PolicyConnector(BaseConnector, PolicyDriver):
     def delete_action(self, policy_id, perimeter_id):
         self.__delete_perimeter(Action, ActionUnknown, policy_id, perimeter_id)
 
+    def __is_perimeter_data_exist(self, ClassType ,data_id=None, category_id=None):
+        logger.info("driver {} {}".format( data_id, category_id))
+        with self.get_session_for_read() as session:
+            query = session.query(ClassType)
+            query = query.filter_by(category_id=category_id)
+            ref_list = query.all()
+            if ref_list:
+                return True
+            return False
+
     def __get_perimeter_data(self, ClassType, policy_id, data_id=None, category_id=None):
         logger.info("driver {} {} {}".format(policy_id, data_id, category_id))
         with self.get_session_for_read() as session:
@@ -602,6 +612,9 @@ class PolicyConnector(BaseConnector, PolicyDriver):
             if ref:
                 session.delete(ref)
 
+    def is_subject_data_exist(self, data_id=None, category_id=None):
+        return self.__is_perimeter_data_exist(SubjectData, data_id=data_id, category_id=category_id)
+
     def get_subject_data(self, policy_id, data_id=None, category_id=None):
         return self.__get_perimeter_data(SubjectData, policy_id, data_id=data_id, category_id=category_id)
 
@@ -614,6 +627,9 @@ class PolicyConnector(BaseConnector, PolicyDriver):
     def delete_subject_data(self, policy_id, data_id):
         return self.__delete_perimeter_data(SubjectData, policy_id, data_id)
 
+    def is_object_data_exist(self, data_id=None, category_id=None):
+        return self.__is_perimeter_data_exist(ObjectData, data_id=data_id, category_id=category_id)
+
     def get_object_data(self, policy_id, data_id=None, category_id=None):
         return self.__get_perimeter_data(ObjectData, policy_id, data_id=data_id, category_id=category_id)
 
@@ -626,6 +642,9 @@ class PolicyConnector(BaseConnector, PolicyDriver):
     def delete_object_data(self, policy_id, data_id):
         return self.__delete_perimeter_data(ObjectData, policy_id, data_id)
 
+    def is_action_data_exist(self, data_id=None,category_id=None):
+        return self.__is_perimeter_data_exist(ActionData, data_id=data_id, category_id=category_id)
+
     def get_action_data(self, policy_id, data_id=None, category_id=None):
         return self.__get_perimeter_data(ActionData, policy_id, data_id=data_id, category_id=category_id)
 
diff --git a/python_moondb/tests/unit_python/models/test_categories.py b/python_moondb/tests/unit_python/models/test_categories.py
index 0ffcf96e..cdcf6bcb 100644
--- a/python_moondb/tests/unit_python/models/test_categories.py
+++ b/python_moondb/tests/unit_python/models/test_categories.py
@@ -1,6 +1,11 @@
-import pytest
-import logging
-from python_moonutilities.exceptions import *
+# Copyright 2018 Open Platform for NFV Project, Inc. and its contributors
+# This software is distributed under the terms and conditions of the 'Apache-2.0'
+# license which can be found in the file 'LICENSE' in this package distribution
+# or at 'http://www.apache.org/licenses/LICENSE-2.0'.
+
+from .test_meta_rules import *
+import policies.mock_data as mock_data
+import policies.test_data as test_data
 
 logger = logging.getLogger("moon.db.tests.models.test_categories")
 
@@ -36,6 +41,55 @@ def test_get_subject_categories_with_invalid_id():
     category_id = "invalid_id"
     subject_category = get_subject_category(category_id)
     assert len(subject_category) == 0
+    category = add_subject_category(value={"name": "category name", "description": "description 1"})
+    assert category is not None
+    with pytest.raises(SubjectCategoryExisting):
+        add_subject_category(value={"name": "category name", "description": "description 2"})
+
+
+def delete_subject_category(cat_id=None):
+    from python_moondb.core import ModelManager
+    ModelManager.delete_subject_category(user_id=None, category_id=cat_id)
+
+
+def test_delete_subject_category(db):
+    category = add_subject_category(value={"name": "category name", "description": "description 1"})
+    delete_subject_category(list(category.keys())[0])
+
+
+def test_delete_subject_category_with_invalid_id(db):
+    with pytest.raises(SubjectCategoryUnknown) as exception_info:
+        delete_subject_category(-1)
+
+
+def test_delete_subject_category_with_meta_rule(db):
+    category = add_subject_category(value={"name": "category name", "description": "description 1"})
+    subject_category_id = list(category.keys())[0]
+    value = {
+        "name": "MLS_meta_rule",
+        "description": "test",
+        "subject_categories": [subject_category_id],
+        "object_categories": ["vm_security_level_id_1"],
+        "action_categories": ["action_type_id_1"]
+    }
+    add_meta_rule(value=value)
+    with pytest.raises(DeleteCategoryWithMetaRule):
+        delete_subject_category(subject_category_id)
+
+
+def test_delete_subject_category_with_data(db):
+    category = add_subject_category(value={"name": "category name", "description": "description 1"})
+    subject_category_id = list(category.keys())[0]
+    policy_id = mock_data.get_policy_id()
+    data_id = "data_id_1"
+    category_id = subject_category_id
+    value = {
+        "name": "subject-security-level",
+        "description": {"low": "", "medium": "", "high": ""},
+    }
+    test_data.add_subject_data(policy_id, data_id, category_id, value)
+    with pytest.raises(DeleteCategoryWithData):
+        delete_subject_category(subject_category_id)
 
 
 def add_object_category(cat_id=None, value=None):
@@ -69,6 +123,55 @@ def test_get_object_categories_with_invalid_id():
     category_id = "invalid_id"
     object_category = get_object_category(category_id)
     assert len(object_category) == 0
+    category = add_object_category(value={"name": "category name", "description": "description 1"})
+    assert category is not None
+    with pytest.raises(ObjectCategoryExisting):
+        add_object_category(value={"name": "category name", "description": "description 2"})
+
+
+def delete_object_category(cat_id=None):
+    from python_moondb.core import ModelManager
+    ModelManager.delete_object_category(user_id=None, category_id=cat_id)
+
+
+def test_delete_object_category(db):
+    category = add_object_category(value={"name": "category name", "description": "description 1"})
+    delete_object_category(list(category.keys())[0])
+
+
+def test_delete_object_category_with_invalid_id(db):
+    with pytest.raises(ObjectCategoryUnknown) as exception_info:
+        delete_object_category(-1)
+
+
+def test_delete_object_category_with_meta_rule(db):
+    category = add_object_category(value={"name": "category name", "description": "description 1"})
+    object_category_id = list(category.keys())[0]
+    value = {
+        "name": "MLS_meta_rule",
+        "description": "test",
+        "subject_categories": ["subject_id_1"],
+        "object_categories": [object_category_id],
+        "action_categories": ["action_type_id_1"]
+    }
+    add_meta_rule(value=value)
+    with pytest.raises(DeleteCategoryWithMetaRule):
+        delete_object_category(object_category_id)
+
+
+def test_delete_object_category_with_data(db):
+    policy_id = mock_data.get_policy_id()
+    category = add_object_category(value={"name": "category name", "description": "description 1"})
+    object_category_id = list(category.keys())[0]
+    data_id = "data_id_1"
+    category_id = object_category_id
+    value = {
+        "name": "object-security-level",
+        "description": {"low": "", "medium": "", "high": ""},
+    }
+    test_data.add_object_data(policy_id, data_id, category_id, value)
+    with pytest.raises(DeleteCategoryWithData):
+        delete_object_category(object_category_id)
 
 
 def add_action_category(cat_id=None, value=None):
@@ -101,4 +204,53 @@ def test_get_action_categories():
 def test_get_action_categories_with_invalid_id():
     category_id = "invalid_id"
     action_category = get_action_category(category_id)
-    assert len(action_category) == 0
\ No newline at end of file
+    assert len(action_category) == 0
+    category = add_action_category(value={"name": "category name", "description": "description 1"})
+    assert category is not None
+    with pytest.raises(ActionCategoryExisting):
+        add_action_category(value={"name": "category name", "description": "description 2"})
+
+
+def delete_action_category(cat_id=None):
+    from python_moondb.core import ModelManager
+    ModelManager.delete_action_category(user_id=None, category_id=cat_id)
+
+
+def test_delete_action_category(db):
+    category = add_action_category(value={"name": "category name", "description": "description 1"})
+    delete_action_category(list(category.keys())[0])
+
+
+def test_delete_action_category_with_invalid_id(db):
+    with pytest.raises(ActionCategoryUnknown) as exception_info:
+        delete_action_category(-1)
+
+
+def test_delete_action_category_with_meta_rule(db):
+    category = add_action_category(value={"name": "category name", "description": "description 1"})
+    action_category_id = list(category.keys())[0]
+    value = {
+        "name": "MLS_meta_rule",
+        "description": "test",
+        "subject_categories": ["subject_id_1"],
+        "object_categories": ["vm_security_level_id_1"],
+        "action_categories": [action_category_id]
+    }
+    add_meta_rule(value=value)
+    with pytest.raises(DeleteCategoryWithMetaRule):
+        delete_action_category(action_category_id)
+
+
+def test_delete_action_category_with_data(db):
+    category = add_action_category(value={"name": "category name", "description": "description 1"})
+    action_category_id = list(category.keys())[0]
+    policy_id = mock_data.get_policy_id()
+    data_id = "data_id_1"
+    category_id = action_category_id
+    value = {
+        "name": "action-type",
+        "description": {"vm-action": "", "storage-action": "", },
+    }
+    test_data.add_action_data(policy_id, data_id, category_id, value)
+    with pytest.raises(DeleteCategoryWithData):
+        delete_action_category(action_category_id)
diff --git a/python_moondb/tests/unit_python/models/test_meta_rules.py b/python_moondb/tests/unit_python/models/test_meta_rules.py
index 585274d9..a5a11552 100644
--- a/python_moondb/tests/unit_python/models/test_meta_rules.py
+++ b/python_moondb/tests/unit_python/models/test_meta_rules.py
@@ -1,4 +1,9 @@
-import pytest
+# Copyright 2018 Open Platform for NFV Project, Inc. and its contributors
+# This software is distributed under the terms and conditions of the 'Apache-2.0'
+# license which can be found in the file 'LICENSE' in this package distribution
+# or at 'http://www.apache.org/licenses/LICENSE-2.0'.
+
+from .test_models import *
 
 
 def set_meta_rule(meta_rule_id, value=None):
@@ -51,7 +56,7 @@ def test_add_new_meta_rule_success(db):
         "object_categories": ["vm_security_level_id_1"],
         "action_categories": ["action_type_id_1"]
     }
-    metaRules = add_meta_rule();
+    metaRules = add_meta_rule()
     assert isinstance(metaRules, dict)
     assert metaRules
     assert len(metaRules) is 1
@@ -172,3 +177,26 @@ def test_delete_invalid_meta_rules_error(db):
     with pytest.raises(Exception) as exception_info:
         delete_meta_rules("INVALID_META_RULE_ID")
     assert str(exception_info.value) == '400: Sub Meta Rule Unknown'
+
+
+def test_delete_meta_rule_with_assigned_model(db):
+    value = {
+        "name": "MLS_meta_rule",
+        "description": "test",
+        "subject_categories": ["user_security_level_id_1"],
+        "object_categories": ["vm_security_level_id_1"],
+        "action_categories": ["action_type_id_1"]
+    }
+    metaRules = add_meta_rule()
+    assert isinstance(metaRules, dict)
+    assert metaRules
+    assert len(metaRules) is 1
+    meta_rule_id = list(metaRules.keys())[0]
+    model_value1 = {
+        "name": "MLS",
+        "description": "test",
+        "meta_rules": meta_rule_id
+    }
+    add_model(value=model_value1)
+    with pytest.raises(DeleteMetaRuleWithModel) as exception_info:
+        delete_meta_rules(meta_rule_id)
diff --git a/python_moondb/tests/unit_python/models/test_models.py b/python_moondb/tests/unit_python/models/test_models.py
index 54c45e77..06c2b6be 100644
--- a/python_moondb/tests/unit_python/models/test_models.py
+++ b/python_moondb/tests/unit_python/models/test_models.py
@@ -1,11 +1,19 @@
+# Copyright 2018 Open Platform for NFV Project, Inc. and its contributors
+# This software is distributed under the terms and conditions of the 'Apache-2.0'
+# license which can be found in the file 'LICENSE' in this package distribution
+# or at 'http://www.apache.org/licenses/LICENSE-2.0'.
+
 import pytest
 from python_moonutilities.exceptions import *
 import logging
+import policies.test_policies as test_policies
+
 logger = logging.getLogger("moon.db.tests.test_model")
 
+
 def get_models(model_id=None):
     from python_moondb.core import ModelManager
-    return ModelManager.get_models(user_id= None , model_id= model_id)
+    return ModelManager.get_models(user_id=None, model_id=model_id)
 
 
 def add_model(model_id=None, value=None):
@@ -62,6 +70,7 @@ def test_get_model(db):
     assert len(models) is 1
     delete_all_models()
 
+
 def test_get_specific_model(db):
     # prepare
     add_model(model_id="mls_model_id")
@@ -74,6 +83,7 @@ def test_get_specific_model(db):
     assert len(models) is 1
     delete_all_models()
 
+
 def test_add_model(db):
     # act
     model = add_model()
@@ -91,7 +101,7 @@ def test_add_same_model_twice(db):
     with pytest.raises(ModelExisting) as exception_info:
         add_model(model_id="model_1")
     delete_all_models()
-    #assert str(exception_info.value) == '409: Model Error'
+    # assert str(exception_info.value) == '409: Model Error'
 
 
 def test_add_model_generate_new_uuid(db):
@@ -175,4 +185,26 @@ def test_update_model(db):
     for key in ("name", "meta_rules", "description"):
         assert key in model[model_id]
         assert model[model_id][key] == new_model_value[key]
-    delete_all_models()
\ No newline at end of file
+    delete_all_models()
+
+
+def test_delete_model_assigned_to_policy(db):
+    model_value1 = {
+        "name": "MLS",
+        "description": "test",
+        "meta_rules": "meta_rule_mls_1"
+    }
+    models = add_model(value=model_value1)
+    assert isinstance(models, dict)
+    assert models
+    assert len(models.keys()) == 1
+    model_id = list(models.keys())[0]
+    value = {
+        "name": "test_policy",
+        "model_id": model_id,
+        "genre": "authz",
+        "description": "test",
+    }
+    test_policies.add_policies(value=value)
+    with pytest.raises(DeleteModelWithPolicy) as exception_info:
+        delete_models(uuid=model_id)
diff --git a/python_moondb/tests/unit_python/policies/test_data.py b/python_moondb/tests/unit_python/policies/test_data.py
index 6a57130e..5e00fe65 100755
--- a/python_moondb/tests/unit_python/policies/test_data.py
+++ b/python_moondb/tests/unit_python/policies/test_data.py
@@ -1,7 +1,10 @@
+# Copyright 2018 Open Platform for NFV Project, Inc. and its contributors
+# This software is distributed under the terms and conditions of the 'Apache-2.0'
+# license which can be found in the file 'LICENSE' in this package distribution
+# or at 'http://www.apache.org/licenses/LICENSE-2.0'.
+
 import policies.mock_data as mock_data
-import pytest
-import logging
-from python_moonutilities.exceptions import *
+from .test_assignments import *
 
 logger = logging.getLogger("python_moondb.tests.api.test_data")
 
@@ -178,6 +181,22 @@ def test_delete_action_data(db):
     assert len(new_action_data[0]['data']) == 0
 
 
+def test_delete_action_data_assigned_to_action_assignment(db):
+    policy_id = mock_data.get_policy_id()
+    get_available_metadata(policy_id)
+    data_id = "data_id_1"
+    category_id = "category_id_1"
+    value = {
+        "name": "action-type",
+        "description": {"vm-action": "", "storage-action": "", },
+    }
+    action_data = add_action_data(policy_id, data_id, category_id, value).get('data')
+    action_data_id = list(action_data.keys())[0]
+    add_action_assignment(policy_id, "action_id_1", category_id, action_data_id)
+    with pytest.raises(DeleteData) as exception_info:
+        delete_action_data(action_data[action_data_id].get('policy_id'), None)
+
+
 def test_get_object_data(db):
     policy_id = mock_data.get_policy_id()
     get_available_metadata(policy_id)
@@ -253,6 +272,22 @@ def test_delete_object_data(db):
     assert len(new_object_data[0]['data']) == 0
 
 
+def test_delete_object_data_assigned_to_object_assignment(db):
+    policy_id = mock_data.get_policy_id()
+    get_available_metadata(policy_id)
+    data_id = "data_id_1"
+    category_id = "category_id_1"
+    value = {
+        "name": "object-type",
+        "description": {"vm-action": "", "storage-action": "", },
+    }
+    object_data = add_object_data(policy_id, data_id, category_id, value).get('data')
+    object_data_id = list(object_data.keys())[0]
+    add_object_assignment(policy_id, "object_id_1", category_id, object_data_id)
+    with pytest.raises(DeleteData) as exception_info:
+        delete_object_data(object_data[object_data_id].get('policy_id'), None)
+
+
 def test_get_subject_data(db):
     policy_id = mock_data.get_policy_id()
     get_available_metadata(policy_id)
@@ -327,6 +362,22 @@ def test_delete_subject_data(db):
     assert len(new_subject_data[0]['data']) == 0
 
 
+def test_delete_subject_data_assigned_to_subject_assignment(db):
+    policy_id = mock_data.get_policy_id()
+    get_available_metadata(policy_id)
+    data_id = "data_id_1"
+    category_id = "category_id_1"
+    value = {
+        "name": "subject-type",
+        "description": {"vm-action": "", "storage-action": "", },
+    }
+    subject_data = add_subject_data(policy_id, data_id, category_id, value).get('data')
+    subject_data_id = list(subject_data.keys())[0]
+    add_subject_assignment(policy_id, "object_id_1", category_id, subject_data_id)
+    with pytest.raises(DeleteData) as exception_info:
+        delete_subject_data(subject_data[subject_data_id].get('policy_id'), None)
+
+
 def test_get_actions(db):
     policy_id = mock_data.get_policy_id()
     value = {
@@ -372,7 +423,9 @@ def test_add_action_multiple_times(db):
         "description": "test",
         "policy_list": ['policy_id_3', 'policy_id_4']
     }
-    action = add_action(mock_data.get_policy_id(model_name="test_model2", policy_name="policy_2", meta_rule_name="meta_rule2", category_prefix="_"), perimeter_id, value)
+    action = add_action(
+        mock_data.get_policy_id(model_name="test_model2", policy_name="policy_2", meta_rule_name="meta_rule2",
+                                category_prefix="_"), perimeter_id, value)
     logger.info("action : {}".format(action))
     assert action
     action_id = list(action.keys())[0]
@@ -444,7 +497,9 @@ def test_add_objects_multiple_times(db):
         "description": "test",
         "policy_list": ['policy_id_3', 'policy_id_4']
     }
-    added_object = add_object(mock_data.get_policy_id(model_name="test_model2", policy_name="policy_2", meta_rule_name="meta_rule2", category_prefix="_"), perimeter_id, value)
+    added_object = add_object(
+        mock_data.get_policy_id(model_name="test_model2", policy_name="policy_2", meta_rule_name="meta_rule2",
+                                category_prefix="_"), perimeter_id, value)
     assert added_object
     object_id = list(added_object.keys())[0]
     assert len(added_object[object_id].get('policy_list')) == 2
@@ -515,7 +570,9 @@ def test_add_subjects_multiple_times(db):
         "description": "test",
         "policy_list": ['policy_id_3', 'policy_id_4']
     }
-    subject = add_subject(mock_data.get_policy_id(model_name="test_model2", policy_name="policy_2", meta_rule_name="meta_rule2", category_prefix="_"), perimeter_id, value)
+    subject = add_subject(
+        mock_data.get_policy_id(model_name="test_model2", policy_name="policy_2", meta_rule_name="meta_rule2",
+                                category_prefix="_"), perimeter_id, value)
     assert subject
     subject_id = list(subject.keys())[0]
     assert len(subject[subject_id].get('policy_list')) == 2
diff --git a/python_moondb/tests/unit_python/policies/test_policies.py b/python_moondb/tests/unit_python/policies/test_policies.py
index f81f0d39..003361d0 100755
--- a/python_moondb/tests/unit_python/policies/test_policies.py
+++ b/python_moondb/tests/unit_python/policies/test_policies.py
@@ -7,6 +7,7 @@ import pytest
 import policies.mock_data as mock_data
 from python_moonutilities.exceptions import *
 
+
 def get_policies():
     from python_moondb.core import PolicyManager
     return PolicyManager.get_policies("admin")
@@ -99,7 +100,7 @@ def test_add_policies_twice_with_same_id(db):
     add_policies(policy_id, value)
     with pytest.raises(PolicyExisting) as exception_info:
         add_policies(policy_id, value)
-    #assert str(exception_info.value) == '409: Policy Error'
+    # assert str(exception_info.value) == '409: Policy Error'
 
 
 def test_delete_policies(db):
@@ -129,7 +130,29 @@ def test_delete_policies_with_invalid_id(db):
     policy_id = 'policy_id_1'
     with pytest.raises(PolicyUnknown) as exception_info:
         delete_policies(policy_id)
-    #assert str(exception_info.value) == '400: Policy Unknown'
+    # assert str(exception_info.value) == '400: Policy Unknown'
+
+
+def test_delete_policies_with_pdp(db):
+    from python_moondb.core import PDPManager
+    value = {
+        "name": "test_policy1",
+        "model_id": "",
+        "genre": "authz",
+        "description": "test",
+    }
+    policies = add_policies(value=value)
+    policy_id1 = list(policies.keys())[0]
+    pdp_id = "pdp_id1"
+    value = {
+        "name": "test_pdp",
+        "security_pipeline": [policy_id1],
+        "keystone_project_id": "keystone_project_id1",
+        "description": "...",
+    }
+    PDPManager.add_pdp(user_id="admin" ,pdp_id=pdp_id, value=value)
+    with pytest.raises(DeletePolicyWithPdp) as exception_info:
+        delete_policies(policy_id1)
 
 
 def test_update_policy(db):
@@ -158,7 +181,7 @@ def test_update_policy_with_invalid_id(db):
     }
     with pytest.raises(PolicyUnknown) as exception_info:
         update_policy(policy_id, value)
-    #assert str(exception_info.value) == '400: Policy Unknown'
+    # assert str(exception_info.value) == '400: Policy Unknown'
 
 
 def test_get_policy_from_meta_rules(db):
@@ -173,7 +196,7 @@ def test_get_policy_from_meta_rules(db):
     policy = add_policies(value=value)
     assert policy
     policy_id = list(policy.keys())[0]
-    pdp_ids = [policy_id,]
+    pdp_ids = [policy_id, ]
     pdp_obj = mock_data.create_pdp(pdp_ids)
     test_pdp.add_pdp(value=pdp_obj)
     matched_policy_id = get_policy_from_meta_rules(meta_rule_id)
@@ -199,7 +222,7 @@ def test_get_policy_from_meta_rules_with_no_policies(db):
     import test_pdp as test_pdp
     meta_rule_id = 'meta_rule_id'
     policy_id = 'invalid'
-    pdp_ids = [policy_id,]
+    pdp_ids = [policy_id, ]
     pdp_obj = mock_data.create_pdp(pdp_ids)
     test_pdp.add_pdp(value=pdp_obj)
     with pytest.raises(Exception) as exception_info:
@@ -217,7 +240,7 @@ def test_get_policy_from_meta_rules_with_no_models(db):
     policy = add_policies(value=value)
     assert policy
     policy_id = list(policy.keys())[0]
-    pdp_ids = [policy_id,]
+    pdp_ids = [policy_id, ]
     pdp_obj = mock_data.create_pdp(pdp_ids)
     test_pdp.add_pdp(value=pdp_obj)
     with pytest.raises(Exception) as exception_info:
diff --git a/python_moonutilities/Changelog b/python_moonutilities/Changelog
index e6ab2f6e..61225b2b 100644
--- a/python_moonutilities/Changelog
+++ b/python_moonutilities/Changelog
@@ -89,4 +89,8 @@ CHANGES
 
 1.4.8
 -----
-- Add SubjectScopeExisting, ObjectScopeExisting, ActionScopeExisting exceptions
\ No newline at end of file
+- Add SubjectScopeExisting, ObjectScopeExisting, ActionScopeExisting exceptions
+
+1.4.9
+-----
+- Add some exceptions when deletion of elements is impossible
diff --git a/python_moonutilities/python_moonutilities/__init__.py b/python_moonutilities/python_moonutilities/__init__.py
index cabb4c52..d313ecc3 100644
--- a/python_moonutilities/python_moonutilities/__init__.py
+++ b/python_moonutilities/python_moonutilities/__init__.py
@@ -3,6 +3,6 @@
 # license which can be found in the file 'LICENSE' in this package distribution
 # or at 'http://www.apache.org/licenses/LICENSE-2.0'.
 
-__version__ = "1.4.8"
+__version__ = "1.4.9"
 
 
diff --git a/python_moonutilities/python_moonutilities/exceptions.py b/python_moonutilities/python_moonutilities/exceptions.py
index f1dcd31e..bb2d35b7 100644
--- a/python_moonutilities/python_moonutilities/exceptions.py
+++ b/python_moonutilities/python_moonutilities/exceptions.py
@@ -651,3 +651,52 @@ class PolicyExisting(MoonError):
     code = 409
     title = 'Policy Error'
     logger = "Error"
+
+
+class DeleteData(MoonError):
+    description = _("Cannot delete data with assignment")
+    code = 400
+    title = 'Data Error'
+    logger = "Error"
+
+
+class DeleteCategoryWithData(MoonError):
+    description = _("Cannot delete category with data")
+    code = 400
+    title = 'Category Error'
+    logger = "Error"
+
+
+class DeleteCategoryWithMetaRule(MoonError):
+    description = _("Cannot delete category with meta rule")
+    code = 400
+    title = 'Category Error'
+    logger = "Error"
+
+
+class DeleteCategoryWithData(MoonError):
+    description = _("Cannot delete category with data")
+    code = 400
+    title = 'Category Error'
+    logger = "Error"
+
+
+class DeleteModelWithPolicy(MoonError):
+    description = _("Cannot delete model with policy")
+    code = 400
+    title = 'Model Error'
+    logger = "Error"
+
+
+class DeletePolicyWithPdp(MoonError):
+    description = _("Cannot delete policy with pdp")
+    code = 400
+    title = 'Policy Error'
+    logger = "Error"
+
+
+class DeleteMetaRuleWithModel(MoonError):
+    description = _("Cannot delete meta rule with model")
+    code = 400
+    title = 'Meta rule Error'
+    logger = "Error"