diff --git a/servers/slapd/back-sql/back-sql.h b/servers/slapd/back-sql/back-sql.h
index 5ec834f695..4046bb3057 100644
--- a/servers/slapd/back-sql/back-sql.h
+++ b/servers/slapd/back-sql/back-sql.h
@@ -96,7 +96,7 @@
 /*
  * define to enable varchars as unique keys in user tables
  */
-#define BACKSQL_ARBITRARY_KEY
+#undef BACKSQL_ARBITRARY_KEY
 
 /*
  * API