diff --git a/dbschema/dbschema.go b/dbschema/dbschema.go
index e18b72d..b1c6030 100644
--- a/dbschema/dbschema.go
+++ b/dbschema/dbschema.go
@@ -3,9 +3,9 @@ package dbschema
 
 const Schema string = `
 CREATE TABLE IF NOT EXISTS presences (
-    id VARCHAR(7) PRIMARY KEY NOT NULL,
+    id VARCHAR(7) PRIMARY KEY,
     at TIMESTAMP NOT NULL,
     name VARCHAR(50) NOT NULL,
-    programme_id NOT NULL
+    programme_id VARCHAR(6) NOT NULL
 );
 `