diff --git a/lib/migration.js b/lib/migration.js
index 1659f9fa..01010b9a 100644
--- a/lib/migration.js
+++ b/lib/migration.js
@@ -823,7 +823,7 @@ function mixinMigration(PostgreSQL) {
           kind = i.kind;
         }
 
-        if (!kind && !type && typeof i === 'object' || i.unique && i.unique === true) {
+        if (!kind && !type && typeof i === 'object' && i.unique && i.unique === true) {
           kind = ' UNIQUE ';
         }