diff --git a/devops/postgres/schema.sql b/devops/postgres/schema.sql
index 788f26ad2b8eb82a6c771cbdc045bb187f30c78a..e88ede55a3e769d35ffc398ef98fe2adc1a2d32e 100644
--- a/devops/postgres/schema.sql
+++ b/devops/postgres/schema.sql
@@ -164,7 +164,7 @@ CREATE TABLE public.context_node_ngrams (
     ngrams_id     INTEGER NOT NULL REFERENCES public.ngrams   (id) ON DELETE CASCADE,
     ngrams_type   INTEGER  ,
     weight double precision,
-    doc_count     INTEGER,
+    doc_count     INTEGER DEFAULT 0,
     PRIMARY KEY (context_id, node_id, ngrams_id, ngrams_type)
   );
 ALTER TABLE public.context_node_ngrams OWNER TO gargantua;
diff --git a/devops/postgres/upgrade/0.0.6.7.3.sql b/devops/postgres/upgrade/0.0.6.7.3.sql
index bd4bd49756f0d22e2d34d4a49d993acfcbada3e8..8b8c0280406381555553dbb5c2b92c1171a1eab7 100644
--- a/devops/postgres/upgrade/0.0.6.7.3.sql
+++ b/devops/postgres/upgrade/0.0.6.7.3.sql
@@ -1,2 +1,2 @@
 ALTER TABLE context_node_ngrams
-  ADD COLUMN doc_count INTEGER;
+  ADD COLUMN doc_count INTEGER DEFAULT 0;