Issue #340 fill null event key

models/staging/stg_ga4__events.sql

@@ -22,11 +22,17 @@ include_session_partition_key as (
         CONCAT(session_key, CAST(event_date_dt as STRING)) as session_partition_key
     from include_session_key
 ),
--- Add unique key for events
+-- Add unique key for events. Potential to not be unique if client_key or session_id is null and uniqueness depends on differentiation by that value.
 include_event_key as (
     select 
         *,
-        to_base64(md5(CONCAT(session_key, event_name, CAST(event_timestamp as STRING), to_json_string(event_params)))) as event_key -- Surrogate key for unique events.  
+        to_base64(md5(ARRAY_TO_STRING([
+            client_key,
+            CAST(session_id as STRING),
+            event_name,
+            CAST(event_timestamp as STRING),
+            to_json_string(event_params)
+        ], ""))) as event_key -- Surrogate key for unique events.  
     from include_session_partition_key
 ),
 detect_gclid as (

models/staging/stg_ga4__events.yml

@@ -7,6 +7,9 @@ models:
       - name: client_key
         description: Surrogate key created from stream_id and user_pseudo_id. Provides a way to uniquely identify a user's device within a stream. Important when using the package to combine data across properties and streams.
       - name: event_key
+        description: >
+          Surrogate key for events. Potential for uniqueness test to fail if client_key or session_id is null
+          and uniqueness depends on differentiation by that value.
         tests:
           - unique
       - name: page_path