Fixing the uid Column isn't unique.

uid is required to be unique for the the Changed Events (with the new Data) to be inserted without creating new Rows.

sql/events/events_create_unique_index_uid.sql

@@ -0,0 +1 @@
+CREATE UNIQUE INDEX idx_events_uid ON events(uid);

sql/events/events_delete_duplicate_rows.sql

@@ -0,0 +1,6 @@
+DELETE FROM events
+WHERE rowid NOT IN (
+  SELECT MIN(rowid)
+  FROM events
+  GROUP BY uid
+);

sql/events/events_find_duplicate_uid.sql

@@ -0,0 +1,4 @@
+SELECT uid, COUNT(*) AS count
+FROM events
+GROUP BY uid
+HAVING COUNT(*) > 1;