diff --git a/crates/core/src/db/datastore/locking_tx_datastore/datastore.rs b/crates/core/src/db/datastore/locking_tx_datastore/datastore.rs
index 8c1fde5f39c..d915f542ac5 100644
--- a/crates/core/src/db/datastore/locking_tx_datastore/datastore.rs
+++ b/crates/core/src/db/datastore/locking_tx_datastore/datastore.rs
@@ -1261,10 +1261,7 @@ mod tests {
     }
 
     fn basic_table_schema() -> TableSchema {
-        TableSchema::new(
-            TableId::SENTINEL,
-            "Foo".into(),
-            map_array(basic_table_schema_cols()),
+        basic_table_schema_with_indices(
             vec![
                 IndexSchema {
                     index_id: IndexId::SENTINEL,
@@ -1297,6 +1294,16 @@ mod tests {
                     }),
                 },
             ],
+        )
+    }
+
+    fn basic_table_schema_with_indices(indices: Vec<IndexSchema>, constraints: Vec<ConstraintSchema>) -> TableSchema {
+        TableSchema::new(
+            TableId::SENTINEL,
+            "Foo".into(),
+            map_array(basic_table_schema_cols()),
+            indices,
+            constraints,
             vec![SequenceSchema {
                 sequence_id: SequenceId::SENTINEL,
                 table_id: TableId::SENTINEL,
@@ -2068,6 +2075,26 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn test_update_no_such_index() -> ResultTest<()> {
+        let datastore = get_datastore()?;
+        let mut tx = datastore.begin_mut_tx(IsolationLevel::Serializable, Workload::ForTests);
+        let schema = basic_table_schema_with_indices([].into(), [].into());
+        let table_id = datastore.create_table_mut_tx(&mut tx, schema)?;
+
+        // There are no indices attached to `table_id`.
+        let index_id = 0.into();
+        let row = to_vec(&u32_str_u32(42, "foo", 24)).unwrap();
+        let err = datastore
+            .update_mut_tx(&mut tx, table_id, index_id, &row)
+            .expect_err("update using a non-existent index should error")
+            .into_index()
+            .expect("the error should be an index error");
+        assert_eq!(err, IndexError::NotFound(index_id));
+
+        Ok(())
+    }
+
     #[test]
     /// Test that two read-only TXes can operate concurrently without deadlock or blocking,
     /// and that both observe correct results for a simple table scan.
diff --git a/crates/core/src/error.rs b/crates/core/src/error.rs
index 469541a42c5..a11c9e3d4d3 100644
--- a/crates/core/src/error.rs
+++ b/crates/core/src/error.rs
@@ -3,6 +3,7 @@ use std::num::ParseIntError;
 use std::path::PathBuf;
 use std::sync::{MutexGuard, PoisonError};
 
+use enum_as_inner::EnumAsInner;
 use hex::FromHexError;
 use spacetimedb_expr::errors::TypingError;
 use spacetimedb_sats::AlgebraicType;
@@ -171,7 +172,7 @@ pub enum SequenceError {
     MultiColumnAutoInc(TableId, ColList),
 }
 
-#[derive(Error, Debug)]
+#[derive(Error, Debug, EnumAsInner)]
 pub enum DBError {
     #[error("LibError: {0}")]
     Lib(#[from] LibError),