diff --git a/rslib/src/notes.rs b/rslib/src/notes.rs
index 7b70659bc..ffe047f4e 100644
--- a/rslib/src/notes.rs
+++ b/rslib/src/notes.rs
@@ -87,7 +87,7 @@ fn row_to_note(row: &Row) -> Result<Note> {
 pub(super) fn set_note(db: &Connection, note: &mut Note, note_type: &NoteType) -> Result<()> {
     note.mtime = TimestampSecs::now();
     // hard-coded for now
-    note.usn = -1;
+    note.usn = Usn(-1);
     let field1_nohtml = strip_html_preserving_image_filenames(&note.fields()[0]);
     let csum = field_checksum(field1_nohtml.as_ref());
     let sort_field = if note_type.sort_field_idx == 0 {
diff --git a/rslib/src/storage/mod.rs b/rslib/src/storage/mod.rs
index a84013282..1fe26fcb7 100644
--- a/rslib/src/storage/mod.rs
+++ b/rslib/src/storage/mod.rs
@@ -1,4 +1,5 @@
 mod sqlite;
 mod timestamp;
+mod usn;
 
 pub(crate) use sqlite::{SqliteStorage, StorageContext};
diff --git a/rslib/src/storage/sqlite.rs b/rslib/src/storage/sqlite.rs
index 083b55e00..6b1a47057 100644
--- a/rslib/src/storage/sqlite.rs
+++ b/rslib/src/storage/sqlite.rs
@@ -297,7 +297,7 @@ impl StorageContext<'_> {
             }
             Ok(*self.usn.as_ref().unwrap())
         } else {
-            Ok(-1)
+            Ok(Usn(-1))
         }
     }
 
diff --git a/rslib/src/storage/usn.rs b/rslib/src/storage/usn.rs
new file mode 100644
index 000000000..d911604af
--- /dev/null
+++ b/rslib/src/storage/usn.rs
@@ -0,0 +1,24 @@
+// Copyright: Ankitects Pty Ltd and contributors
+// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+
+use crate::types::Usn;
+use rusqlite::{
+    types::{FromSql, FromSqlError, ToSqlOutput, Value, ValueRef},
+    ToSql,
+};
+
+impl FromSql for Usn {
+    fn column_result(value: ValueRef<'_>) -> std::result::Result<Self, FromSqlError> {
+        if let ValueRef::Integer(i) = value {
+            Ok(Self(i as i32))
+        } else {
+            Err(FromSqlError::InvalidType)
+        }
+    }
+}
+
+impl ToSql for Usn {
+    fn to_sql(&self) -> rusqlite::Result<rusqlite::types::ToSqlOutput<'_>> {
+        Ok(ToSqlOutput::Owned(Value::Integer(self.0 as i64)))
+    }
+}
diff --git a/rslib/src/timestamp.rs b/rslib/src/timestamp.rs
index 35089b36f..79d86685a 100644
--- a/rslib/src/timestamp.rs
+++ b/rslib/src/timestamp.rs
@@ -4,7 +4,7 @@
 use std::time;
 
 #[repr(transparent)]
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Copy)]
 pub struct TimestampSecs(pub i64);
 
 impl TimestampSecs {
@@ -14,7 +14,7 @@ impl TimestampSecs {
 }
 
 #[repr(transparent)]
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Copy)]
 pub struct TimestampMillis(pub i64);
 
 impl TimestampMillis {
diff --git a/rslib/src/types.rs b/rslib/src/types.rs
index 51d66858c..8912fd3cf 100644
--- a/rslib/src/types.rs
+++ b/rslib/src/types.rs
@@ -5,4 +5,7 @@
 // signed integers, so these numbers are signed as well.
 
 pub type ObjID = i64;
-pub type Usn = i32;
+
+#[repr(transparent)]
+#[derive(Debug, Clone, Copy)]
+pub struct Usn(pub i32);