start simple examples

examples/simple-rust/demo.rs

@@ -0,0 +1,53 @@
+use rusqlite::{ffi::sqlite3_auto_extension, Connection, Result};
+use sqlite_vec::sqlite3_vec_init;
+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 (sqlite_version, vec_version, x): (String, String, String) = db.query_row(
+        "select sqlite_version(), vec_version(), vec_to_json(?)",
+        &[v.as_bytes()],
+        |x| Ok((x.get(0)?, x.get(1)?, x.get(2)?)),
+    )?;
+
+    println!("sqlite_version={sqlite_version}, vec_version={vec_version}");
+
+    let items: Vec<(usize, Vec<f32>)> = vec![
+        (1, vec![0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8]),
+        (2, vec![0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8]),
+    ];
+    println!("{x}");
+
+    db.execute(
+        "CREATE VIRTUAL TABLE vec_items USING vec0(embedding float[8])",
+        [],
+    )?;
+    let mut stmt = db.prepare("INSERT INTO vec_items(rowid, embedding) VALUES (?, ?)")?;
+    for item in items {
+        stmt.execute(rusqlite::params![item.0, item.1.as_bytes()])?;
+    }
+
+    let query: Vec<f32> = vec![0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8];
+    let result: Vec<(i64, f64)> = db
+        .prepare(
+            r"
+          SELECT
+            rowid,
+            distance
+          FROM vec_items
+          WHERE embedding MATCH ?1
+          ORDER BY distance
+          LIMIT 5
+        ",
+        )?
+        .query_map([query.as_bytes()], |r| Ok((r.get(0)?, r.get(1)?)))?
+        .collect::<Result<Vec<_>, _>>()?;
+    println!("{:?}", result);
+    Ok(())
+}