diff --git a/databases/core.py b/databases/core.py
index 727802d4..839e58f5 100644
--- a/databases/core.py
+++ b/databases/core.py
@@ -62,7 +62,7 @@ def __init__(
 
         self._force_rollback = force_rollback
 
-        backend_str = self.SUPPORTED_BACKENDS[self.url.scheme]
+        backend_str = self._get_backend()
         backend_cls = import_from_string(backend_str)
         assert issubclass(backend_cls, DatabaseBackend)
         self._backend = backend_cls(self.url, **self.options)
@@ -329,6 +329,13 @@ def _build_query(
 
         return query
 
+    def _get_backend(self) -> Optional[str]:
+        try:
+            return self.SUPPORTED_BACKENDS[self.url.scheme]
+        except KeyError:
+            return self.SUPPORTED_BACKENDS[self.url.dialect]
+
+
 
 class Transaction:
     def __init__(