diff --git a/dbt/adapters/factory.py b/dbt/adapters/factory.py
index b1854f67..8a018619 100644
--- a/dbt/adapters/factory.py
+++ b/dbt/adapters/factory.py
@@ -188,7 +188,7 @@ def get_include_paths(self, name: Optional[str]) -> List[Path]:
     def get_adapter_type_names(self, name: Optional[str]) -> List[str]:
         return [p.adapter.type() for p in self.get_adapter_plugins(name)]
 
-    def get_adapter_constraint_support(self, name: Optional[str]) -> List[str]:
+    def get_adapter_constraint_support(self, name: Optional[str]) -> Dict[str, str]:
         return self.lookup_adapter(name).CONSTRAINT_SUPPORT  # type: ignore
 
 
@@ -251,7 +251,7 @@ def get_adapter_type_names(name: Optional[str]) -> List[str]:
     return FACTORY.get_adapter_type_names(name)
 
 
-def get_adapter_constraint_support(name: Optional[str]) -> List[str]:
+def get_adapter_constraint_support(name: Optional[str]) -> Dict[str, str]:
     return FACTORY.get_adapter_constraint_support(name)