修正

backend/sql/schema.sql

@@ -0,0 +1,47 @@
+CREATE OR REPLACE FUNCTION fn_check_month_locked(p_date date)
+RETURNS void
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    IF EXISTS (
+        SELECT 1
+          FROM month_locks
+         WHERE lock_month = date_trunc('month', p_date)
+           AND is_locked = true
+    ) THEN
+        RAISE EXCEPTION
+            '该月份已锁定，不能操作该仕訳（%）',
+            to_char(p_date, 'YYYY-MM');
+    END IF;
+END;
+$$;
+
+CREATE OR REPLACE FUNCTION trg_journal_entries_month_lock()
+RETURNS trigger
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    IF TG_OP = 'INSERT' THEN
+        PERFORM fn_check_month_locked(NEW.journal_date);
+        RETURN NEW;
+    END IF;
+
+    IF TG_OP = 'UPDATE' THEN
+        PERFORM fn_check_month_locked(OLD.journal_date);
+        RETURN NEW;
+    END IF;
+
+    IF TG_OP = 'DELETE' THEN
+        PERFORM fn_check_month_locked(OLD.journal_date);
+        RETURN OLD;
+    END IF;
+
+    RETURN NULL;
+END;
+$$;
+
+CREATE TRIGGER trg_journal_entries_month_lock
+BEFORE INSERT OR UPDATE OR DELETE
+ON journal_entries
+FOR EACH ROW
+EXECUTE FUNCTION trg_journal_entries_month_lock();