Added is_attribute to EntityPath and sub_schemata to EntitySchema. (#11)

* Added is_attribute to EntityPath

* Added sub_schemata to EntitySchema

* Added doc to sub_schemata

* Fixed doc for sub_schemata

* Fixed doc for sub_schemata

* Renamed EntitySchema and EntityPath attributes.

cmem_plugin_base/dataintegration/entity.py

@@ -5,31 +5,40 @@
 class EntityPath:
     """A path in a schema.
 
-    :param path: The path string using the Silk path language.
-    :param is_uri: If true, values for this path must only contain URIs that point to
-    a sub entity.
+    :param is_relation: If true, values for this path must only contain URIs that
+    point to a sub entity.
+    :param is_single_value If true, a single value is expected and supporting datasets
+    will not use arrays etc. For instance, in XML, attributes will be used instead of
+    nested elements.
     """
 
-    def __init__(self, path: str, is_uri: bool = False) -> None:
+    def __init__(self, path: str,
+                 is_relation: bool = False,
+                 is_single_value: bool = False) -> None:
         self.path = path
-        self.is_uri = is_uri
+        self.is_relation = is_relation
+        self.is_single_value = is_single_value
 
 
 class EntitySchema:
     """An entity schema.
 
     :param type_uri: The entity type
     :param paths: Ordered list of paths
-    :param sub_path: Path starting from the root for enumerating the entities.
+    :param path_to_root: Specifies a path which defines where this schema is located
+    in the schema tree
+    :param sub_schemata: Nested entity schemata
     """
 
     def __init__(self,
                  type_uri: str,
                  paths: Sequence[EntityPath],
-                 sub_path: EntityPath = EntityPath("")) -> None:
+                 path_to_root: EntityPath = EntityPath(""),
+                 sub_schemata: Optional[Sequence['EntitySchema']] = None) -> None:
         self.type_uri = type_uri
         self.paths = paths
-        self.sub_path = sub_path
+        self.path_to_root = path_to_root
+        self.sub_schemata = sub_schemata
 
 
 class Entity: