diff --git a/src/Common/EntityResolver.php b/src/Common/EntityResolver.php
index 95e90f9..04f93c8 100644
--- a/src/Common/EntityResolver.php
+++ b/src/Common/EntityResolver.php
@@ -170,9 +170,9 @@ class EntityResolver {
         return $table;
     }
 
-    public function databaseName() : string
+    public function databaseName() : ? string
     {
-        return $this->tableAnnotation(false)->database ?? $this->databaseAdapter()->adapter()->database;
+        return $this->tableAnnotation(false)->database ?? $this->databaseAdapter()->adapter()->database ?? null;
     }
 
     public function sqlAdapter() : \Ulmus\ConnectionAdapter
diff --git a/src/ConnectionAdapter.php b/src/ConnectionAdapter.php
index 2964efe..97d37f5 100644
--- a/src/ConnectionAdapter.php
+++ b/src/ConnectionAdapter.php
@@ -41,7 +41,7 @@ class ConnectionAdapter
 
     public function getConfiguration() : array
     {
-        return $this->configuration['connections'][$this->name];
+        return $this->configuration['connections'][$this->name] ?? [];
     }
 
     /**
diff --git a/src/Query/Set.php b/src/Query/Set.php
index a3ddce4..b97e023 100644
--- a/src/Query/Set.php
+++ b/src/Query/Set.php
@@ -27,7 +27,7 @@ class Set extends Fragment {
         return $this;
     }
 
-    public function render() : string
+    public function render() /* : mixed */
     {                    
         return $this->renderSegments([
             'SET', $this->renderParameterPlaceholders(),
diff --git a/src/Query/Where.php b/src/Query/Where.php
index 72e7b17..851ec1d 100644
--- a/src/Query/Where.php
+++ b/src/Query/Where.php
@@ -114,7 +114,7 @@ class Where extends Fragment {
                 }
 
                 # whitelisting operators
-                return in_array(strtoupper($this->operator), [ '=', '!=', '<>', 'LIKE' ]) ? $this->operator : "=";
+                return in_array(strtoupper($this->operator), [ '=', '!=', '<>', 'LIKE', 'IS', 'IS NOT' ]) ? $this->operator : "=";
             }
 
             protected function value()
diff --git a/src/Repository.php b/src/Repository.php
index 8ce8bc6..9f1f97d 100644
--- a/src/Repository.php
+++ b/src/Repository.php
@@ -161,6 +161,7 @@ class Repository
 
                 $entity->entityFillFromDataset($dataset);
 
+
                 return $update ? (bool) $update->rowCount() : false;
             }
         }
@@ -612,7 +613,7 @@ class Repository
         return Ulmus::datasetQueryBuilder($this->queryBuilder, $this->adapter);
     }
 
-    public function runQuery() : ? \PDOStatement
+    public function runQuery() /* : mixed */
     {
         $this->finalizeQuery();