diff --git a/heromodels/examples/postgres_model_example.rs b/heromodels/examples/postgres_model_example.rs
index 437173b..fcc5a9a 100644
--- a/heromodels/examples/postgres_model_example.rs
+++ b/heromodels/examples/postgres_model_example.rs
@@ -179,6 +179,12 @@ fn main() {
         print_user_details(inactive_user);
     }
 
+    // Delete a user based on an index for good measure
+    db.collection::<User>()
+        .expect("can open user collection")
+        .delete::<username, _>("janesmith")
+        .expect("can delete existing user");
+
     println!("\n--- User Model Information ---");
     println!("User DB Prefix: {}", User::db_prefix());
 
diff --git a/heromodels/src/db.rs b/heromodels/src/db.rs
index 1576c2f..ed8c3fa 100644
--- a/heromodels/src/db.rs
+++ b/heromodels/src/db.rs
@@ -28,7 +28,7 @@ where
     where
         I: Index<Model = V>,
         I::Key: Borrow<Q>,
-        Q: ToString + ?Sized;
+        Q: ToString + Serialize + core::fmt::Debug + Sync + ?Sized;
 
     /// Get an object from its ID. This does not use an index lookup
     fn get_by_id(&self, id: u32) -> Result<Option<V>, Error<Self::Error>>;
@@ -49,7 +49,7 @@ where
     where
         I: Index<Model = V>,
         I::Key: Borrow<Q>,
-        Q: ToString + ?Sized;
+        Q: ToString + Serialize + core::fmt::Debug + Sync + ?Sized;
 
     /// Delete an object with a given ID
     fn delete_by_id(&self, id: u32) -> Result<(), Error<Self::Error>>;
diff --git a/heromodels/src/db/hero.rs b/heromodels/src/db/hero.rs
index 61beb2f..1bff959 100644
--- a/heromodels/src/db/hero.rs
+++ b/heromodels/src/db/hero.rs
@@ -8,8 +8,8 @@ use std::{
     collections::HashSet,
     path::PathBuf,
     sync::{
-        Arc, Mutex,
         atomic::{AtomicU32, Ordering},
+        Arc, Mutex,
     },
 };
 
diff --git a/heromodels/src/db/postgres.rs b/heromodels/src/db/postgres.rs
index b807986..ca466cc 100644
--- a/heromodels/src/db/postgres.rs
+++ b/heromodels/src/db/postgres.rs
@@ -5,6 +5,7 @@ use postgres::types::Json;
 use postgres::{Client, NoTls};
 use r2d2::Pool;
 use r2d2_postgres::PostgresConnectionManager;
+use serde::Serialize;
 
 #[derive(Clone)]
 pub struct Postgres {
@@ -165,7 +166,7 @@ where
     where
         I: heromodels_core::Index<Model = M>,
         I::Key: std::borrow::Borrow<Q>,
-        Q: ToString + ?Sized,
+        Q: ToString + Serialize + core::fmt::Debug + Sync + ?Sized,
     {
         let mut con = self.pool.get().map_err(Error::from)?;
 
@@ -175,7 +176,7 @@ where
                     "SELECT (value) FROM {} WHERE value->$1 = $2;",
                     Self::collection_name::<M>(),
                 ),
-                &[&I::key(), &key.to_string()],
+                &[&I::field_name(), &Json(key)],
             )
             .map_err(Error::from)?
             .into_iter()
@@ -277,7 +278,7 @@ where
     where
         I: heromodels_core::Index<Model = M>,
         I::Key: std::borrow::Borrow<Q>,
-        Q: ToString + ?Sized,
+        Q: ToString + Serialize + core::fmt::Debug + Sync + ?Sized,
     {
         let mut con = self.pool.get().map_err(Error::from)?;
 
@@ -286,7 +287,7 @@ where
                 "DELETE FROM {} WHERE value->$1 = $2;",
                 Self::collection_name::<M>()
             ),
-            &[&I::key(), &key.to_string()],
+            &[&I::field_name(), &Json(key)],
         )
         .map_err(Error::from)?;