add sqlite serialize/deserialize example

- Use SqliteOwnedBuf with serialize/deserialize to snapshot
  an in-memory database as raw bytes
- Embed the bytes in a custom container format (magic header + db)
- Round-trip: create → serialize → write → read → deserialize → query

Author: mattrighetti

Cargo.lock

@@ -24,6 +24,7 @@ members = [
     "examples/postgres/transaction",
     "examples/sqlite/todos",
     "examples/sqlite/extension",
+    "examples/sqlite/serialize",
 ]
 
 [workspace.package]

Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "sqlx-example-sqlite-serialize"
+version = "0.1.0"
+edition = "2024"
+workspace = "../../../"
+
+[dependencies]
+anyhow = "1.0"
+sqlx = { path = "../../../", features = ["sqlite", "sqlite-deserialize", "runtime-tokio"] }
+tokio = { version = "1", features = ["rt", "macros"] }

examples/sqlite/serialize/Cargo.toml

@@ -0,0 +1,31 @@
+use sqlx::sqlite::SqliteOwnedBuf;
+use sqlx::{Connection, SqliteConnection};
+
+#[tokio::main(flavor = "current_thread")]
+async fn main() -> anyhow::Result<()> {
+    let mut conn = SqliteConnection::connect("sqlite::memory:").await?;
+
+    sqlx::raw_sql(
+        "create table notes(id integer primary key, body text not null);
+         insert into notes(body) values ('hello'), ('world');",
+    )
+    .execute(&mut conn)
+    .await?;
+
+    let snapshot: SqliteOwnedBuf = conn.serialize(None).await?;
+    let bytes: &[u8] = snapshot.as_ref();
+    conn.close().await?;
+
+    let owned = SqliteOwnedBuf::try_from(bytes)?;
+    let mut restored = SqliteConnection::connect("sqlite::memory:").await?;
+    restored.deserialize(None, owned, false).await?;
+
+    let rows = sqlx::query_as::<_, (i64, String)>("select id, body from notes order by id")
+        .fetch_all(&mut restored)
+        .await?;
+
+    assert_eq!(rows.len(), 2);
+    assert_eq!(rows[0].1, "hello");
+    assert_eq!(rows[1].1, "world");
+    Ok(())
+}