Set a default dashboard if none exists

python/nav/models/sql/changes/sc.05.12.0001.sql

@@ -0,0 +1,20 @@
+-- This migration is to ensure that for accounts that don't have a default
+-- dashboard we set a default dashboard
+
+-- This part finds the row with the lowest id for any account that does not
+-- have a default dashboard
+WITH CTE AS (
+  SELECT MIN(id) as id
+  FROM account_dashboard a
+  WHERE NOT EXISTS (
+    SELECT 1 
+    FROM account_dashboard b 
+    WHERE a.account_id = b.account_id 
+    AND b.is_default = TRUE
+  )
+  GROUP BY account_id
+)
+-- And this part sets is_default for that row to true
+UPDATE account_dashboard
+SET is_default = TRUE
+WHERE id IN (SELECT id FROM CTE);