diff --git a/heromodels/src/db/postgres.rs b/heromodels/src/db/postgres.rs
index 73b4179..4f4247f 100644
--- a/heromodels/src/db/postgres.rs
+++ b/heromodels/src/db/postgres.rs
@@ -76,6 +76,8 @@ pub enum Error {
     FailedUpdate(usize),
     /// We tried to query the existence of a table but it failed
     TableExistenceQuery,
+    /// Transactions aren't supported
+    Transaction,
 }
 
 impl Postgres {
@@ -334,7 +336,7 @@ where
     fn begin_transaction(
         &self,
     ) -> Result<Box<dyn super::Transaction<Error = Self::Error>>, super::Error<Self::Error>> {
-        todo!()
+        Err(Error::Transaction.into())
     }
 }
 
@@ -356,6 +358,7 @@ impl core::fmt::Display for Error {
                 "update did not return the expected 1 modified row (got {amount})"
             )),
             Self::TableExistenceQuery => f.write_str("query to check if table exists failed"),
+            Self::Transaction => f.write_str("transactions aren't supported"),
         }
     }
 }