Merge pull request #723 from hmcts/defect/pdda-594

PDDA-594 Adding unique constraint to xhb_hearing to prevent duplicate…

Author: gittinsl

src/main/resources/database/scripts/V1_5_2__pdda-amend-constraints.sql

@@ -0,0 +1,6 @@
+ALTER TABLE xhb_hearing
+DROP CONSTRAINT IF EXISTS hearing_unique;
+
+ALTER TABLE xhb_hearing
+ADD CONSTRAINT hearing_unique
+UNIQUE (court_id, case_id, ref_hearing_type_id, hearing_start_date);