sqlite-vec/site/using/rust.md

Using sqlite-vec in Rust

You can embed sqlite-vec into your Rust projects using the official sqlite-vec crate.

cargo add sqlite-vec

The crate embeds the sqlite-vec C source code, and uses the cc crate to compile and statically link sqlite-vec at build-time.

The sqlite-vec crate exposes a single function sqlite3_vec_init, which is the C entrypoint for the SQLite extension. You can "register" with your Rust SQLite library's sqlite3_auto_extension() function.

This example registers sqlite-vec using rusqlite. First, enable the "bundled" feature in your Cargo file entry for rusqlite:

# Cargo.toml
[dependencies]
+ rusqlite = { version = "VERSION", features = ["bundled"] }

Then, you can verify your installation was successful by embedding your first vector. This example uses zerocopy to efficiently pass the vector as bytes, and prints the resulting vector and library version as Strings:

use sqlite_vec::sqlite3_vec_init;
use rusqlite::{ffi::sqlite3_auto_extension, Result};
use zerocopy::AsBytes;

fn main()-> Result<()> {
    unsafe {
        sqlite3_auto_extension(Some(std::mem::transmute(sqlite3_vec_init as *const ())));
    }

    let db = Connection::open_in_memory()?;
    let v: Vec<f32> = vec![0.1, 0.2, 0.3];

    let (vec_version, embedding): (String, String) = db.query_row(
        "select  vec_version(), vec_to_json(?)",
        &[v.as_bytes()],
        |x| Ok((x.get(0)?, x.get(1)?)),
    )?;

    println!("vec_version={vec_version}, embedding={embedding}");
    Ok(())
}

See simple-rust/demo.rs for a more complete Rust demo.

Working with vectors in Rust

If your vectors are provided as a Vec<f32> type, the zerocopy crate is recommended, specifically zerocopy::AsBytes. This will allow you to pass in vectors into sqlite-vec without any copying.

let query: Vec<f32> = vec![0.1, 0.2, 0.3, 0.4];
let mut stmt = db.prepare("SELECT vec_length(?)")?;
stmt.execute(&[item.1.as_bytes()])?;