ref: add 'update' method for future use in cached API interrogator

Author: paulmueller

dcoraid/dbmodel/db_api.py

@@ -255,6 +255,10 @@ def search_dataset_via_api(self,
 
         return dbextract
 
+    def update(self, reset=False):
+        """Ignored, since no local database exists"""
+        pass
+
     @property
     def local_timestamp(self):
         """Local database date in seconds since epoch"""

dcoraid/dbmodel/db_core.py

@@ -88,3 +88,8 @@ def remote_version_score(self):
     def remote_timestamp(self):
         """Remote database date in seconds since epoch"""
         return 0
+
+    @abc.abstractmethod
+    def update(self, reset=False):
+        """Update the local database copy"""
+        pass