diff --git a/src/data/bigquery_table.rs b/src/data/bigquery_table.rs
index 4f6592d..79b1d8d 100644
--- a/src/data/bigquery_table.rs
+++ b/src/data/bigquery_table.rs
@@ -214,7 +214,7 @@ pub trait BigQueryTable: BigQueryTableBase {
     }
 
     /// proxy for update
-    async fn save(&mut self) -> Result<()>
+    async fn save(&self) -> Result<()>
     where
         Self: Sized + Clone + Send + Sync + Debug + Default,
     {