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. Here's an example with rusqlite:

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

fn main()-> Result<()> {
    unsafe {
        sqlite3_auto_extension(Some(std::mem::transmute(sqlite3_vec_init as *const ())));
    }
    // future database connection will now automatically include sqlite-vec functions!
    let db = Connection::open_in_memory()?;
    let vec_version: String = db.query_row("select vec_version()", &[v.as_bytes()], |x| x.get(0)?)?;

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

A full sqlite-vec Rust demo is also available.

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()])?;