Ensure only one dashboard per user is default

python/nav/models/sql/changes/sc.05.12.0002.sql

@@ -0,0 +1,21 @@
+-- This migration is to ensure that for accounts that have more than one
+-- default dashboard we set is_default to false for all except for one
+
+UPDATE account_dashboard
+SET is_default = FALSE
+WHERE id NOT IN (
+  -- This part finds the lowest id of the default dashboards for each
+  -- account_id 
+  SELECT MIN(id)
+  FROM account_dashboard
+  WHERE is_default = TRUE
+  GROUP BY account_id
+)
+AND account_id IN (
+  -- This part finds all account_ids that have more than one default dashboard
+  SELECT account_id
+  FROM account_dashboard
+  WHERE is_default = TRUE
+  GROUP BY account_id
+  HAVING COUNT(account_id) > 1
+)