ENH: Allow internal properties in the extern keyword of yaml models

src/caosadvancedtools/models/data_model.py

@@ -33,6 +33,12 @@ import caosdb as db
 from caosdb.apiutils import compare_entities, describe_diff
 
 
+CAOSDB_INTERNAL_PROPERTIES = [
+    "name",
+    "unit",
+]
+
+
 class DataModel(dict):
     """Provides tools for managing a data model.
 
@@ -129,8 +135,13 @@ class DataModel(dict):
             any_change = False
 
             for ent in existing_entities:
-                q = db.Query("FIND * with id={}".format(ent.id))
-                ref = q.execute(unique=True)
+                if ent.name in CAOSDB_INTERNAL_PROPERTIES:
+                    # Workaround for the usage of internal properties like name
+                    # in via the extern keyword:
+                    ref = db.Property(name=ent.name).retrieve()
+                else:
+                    q = db.Query("FIND * with id={}".format(ent.id))
+                    ref = q.execute(unique=True)
                 diff = (describe_diff(*compare_entities(ent, ref
                                                         ), name=ent.name))
 

src/caosadvancedtools/models/parser.py

@@ -22,7 +22,7 @@ import sys
 import caosdb as db
 import yaml
 
-from .data_model import DataModel
+from .data_model import CAOSDB_INTERNAL_PROPERTIES, DataModel
 
 # Keywords which are allowed in data model descriptions.
 KEYWORDS = ["parent",  # deprecated, use inherit_from_* instead:
@@ -186,6 +186,9 @@ class Parser(object):
             ymlmodel["extern"] = []
 
         for name in ymlmodel["extern"]:
+            if name in CAOSDB_INTERNAL_PROPERTIES:
+                self.model[name] = db.Property(name=name).retrieve()
+                continue
             for role in ("Property", "RecordType", "Record", "File"):
                 if db.execute_query("COUNT {} {}".format(role, name)) > 0:
                     self.model[name] = db.execute_query(