diff --git a/download.py b/download.py
index 5c0d49b..ed09b61 100644
--- a/download.py
+++ b/download.py
@@ -75,8 +75,9 @@ def validate_file(source):
 
     # are expected columns present?
     columns = [x.lower() for x in df.columns]
-    if source["primary_key"]:
-        if source["primary_key"] not in columns:
+    # is primary key present and not null?
+    if "primary_key" in source and source["primary_key"]:
+        if source["primary_key"].lower() not in columns:
             raise ValueError(
                 f"Validation error: {source['alias']} - primary key is not present - {source['primary_key']}"
             )
@@ -110,8 +111,8 @@ def validate_bcgw(source):
     table_def = bcdata.get_table_definition(table)
     columns = [c["column_name"] for c in table_def["schema"]]
 
-    # is primary key present?
-    if source["primary_key"]:
+    # is primary key present and not null?
+    if "primary_key" in source and source["primary_key"]:
         if source["primary_key"] not in columns:
             raise ValueError(
                 f"Validation error: {source['alias']} - Primary key - {source['primary_key']} is not present in {table}"
diff --git a/sources.json b/sources.json
index 18f70aa..f9b8455 100644
--- a/sources.json
+++ b/sources.json
@@ -429,9 +429,7 @@
         "source_type": "FILE",
         "layer": "GBRSchD_GB_20151105",
         "query": "GB_CLASS = 2",
-        "field_mapper": {
-            "name": "GB_CLASS"
-        },
+        "field_mapper": {"name": "GB_CLASS"},
         "data": {"harvest_restriction": 5}
     },
     {
@@ -441,9 +439,7 @@
         "source_type": "FILE",
         "layer": "BC_Boundary_Terrestrial_Singlepart",
         "query": null,
-        "field_mapper": {
-            "name": null
-        },
+        "field_mapper": {"name": null},
         "data": {"harvest_restriction": 6}
     }
 ]
\ No newline at end of file