AB#101818 Skip id fields if this is only an internal field

Some id fields are only there to give Django a non-composite PK.

Author: jjmurre

src/schematools/exports/__init__.py

@@ -128,5 +128,7 @@ def _get_fields(dataset_schema: DatasetSchema, table: DatasetTableSchema, scopes
     for field in table.fields:
         if field.is_array:
             continue
+        if field.is_internal:
+            continue
         if parent_scopes | set(field.auth) - {_PUBLIC_SCOPE} <= set(scopes):
             yield field

src/schematools/types.py

@@ -1434,6 +1434,11 @@ def is_identifier_part(self) -> bool:
             self.id == "id" or self._id in self._parent_table.identifier
         ) and self._parent_field is None
 
+    @cached_property
+    def is_internal(self) -> bool:
+        """Id fields for table with composite key is only for internal (Django) use."""
+        return self.is_primary and self._parent_table.has_composite_key
+
     @cached_property
     def relation(self) -> str | None:
         """Give the 1:N relation, if it exists."""

tests/test_export.py

@@ -37,7 +37,7 @@ def test_csv_export_only_actual(here, engine, ggwgebieden_schema, dbsession, tmp
     with open(tmp_path / "ggwgebieden_ggwgebieden.csv") as out_file:
         lines = out_file.readlines()
         assert len(lines) == 2  # includes the headerline
-        assert lines[1].split(",")[1] == "2"  # volgnummer == 2
+        assert lines[1].split(",")[0] == "2"  # volgnummer == 2
 
 
 def test_jsonlines_export(here, engine, meetbouten_schema, dbsession, tmp_path):