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lancedb/docs/web-tests/rs/quickstart.rs
T
Brendan Clement 30c973e64c docs: make the TypeScript and Rust quickstarts complete programs
The TypeScript connection example only defined a helper that nothing
called, so every later step failed with `db is not defined`. It now
connects, as the Python one does. The Rust one kept its connection
inside a helper, the Enterprise one read its settings without
connecting, and the later steps relied on imports and a record-batch
helper the page never showed.

The quickstart now says how the steps make one program: an ES module
run with Node in TypeScript, and the body of an async `main` in Rust,
whose dependencies the install step lists. Each Rust step brings its own
imports, the data step shows the helper that turns the records into a
reader, and Arrow comes from lancedb's re-exports, so no Arrow crate is
needed. The row structs no longer derive serde traits nothing used.

The connection examples are shared, so the connect, create-table and
branching pages gain the import line their connection code now needs.
2026-10-09 17:28:57 -07:00

370 lines
12 KiB
Rust

// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright The LanceDB Authors
use lancedb::{connect, table::NewColumnTransform};
// --8<-- [start:quickstart_define_struct]
use std::sync::Arc;
use lancedb::arrow::arrow_array::types::Float32Type;
use lancedb::arrow::arrow_array::{
FixedSizeListArray, Int8Array, LargeStringArray, RecordBatch, RecordBatchIterator,
RecordBatchReader, StructArray,
};
use lancedb::arrow::arrow_schema::{DataType, Field, FieldRef, Fields, Schema};
// Define structs representing the data schema
#[derive(Debug, Clone)]
struct Stats {
strength: i8,
magic: i8,
leadership: i8,
wisdom: i8,
}
#[derive(Debug, Clone)]
struct Character {
id: String,
name: String,
role: String,
description: String,
stats: Stats,
vector: [f32; 4],
}
fn characters_schema() -> Arc<Schema> {
Arc::new(Schema::new(vec![
Field::new("id", DataType::LargeUtf8, false),
Field::new("name", DataType::LargeUtf8, false),
Field::new("role", DataType::LargeUtf8, false),
Field::new("description", DataType::LargeUtf8, false),
Field::new(
"stats",
DataType::Struct(Fields::from(vec![
Arc::new(Field::new("strength", DataType::Int8, false)),
Arc::new(Field::new("magic", DataType::Int8, false)),
Arc::new(Field::new("leadership", DataType::Int8, false)),
Arc::new(Field::new("wisdom", DataType::Int8, false)),
])),
false,
),
Field::new(
"vector",
DataType::FixedSizeList(Arc::new(Field::new("item", DataType::Float32, true)), 4),
false,
),
]))
}
fn characters_to_reader(
schema: Arc<Schema>,
rows: &[Character],
) -> Box<dyn RecordBatchReader + Send> {
let ids = LargeStringArray::from_iter_values(rows.iter().map(|row| row.id.as_str()));
let names = LargeStringArray::from_iter_values(rows.iter().map(|row| row.name.as_str()));
let roles = LargeStringArray::from_iter_values(rows.iter().map(|row| row.role.as_str()));
let descriptions =
LargeStringArray::from_iter_values(rows.iter().map(|row| row.description.as_str()));
let strength = Int8Array::from_iter_values(rows.iter().map(|row| row.stats.strength));
let magic = Int8Array::from_iter_values(rows.iter().map(|row| row.stats.magic));
let leadership = Int8Array::from_iter_values(rows.iter().map(|row| row.stats.leadership));
let wisdom = Int8Array::from_iter_values(rows.iter().map(|row| row.stats.wisdom));
let stats_fields: Vec<FieldRef> = vec![
Arc::new(Field::new("strength", DataType::Int8, false)),
Arc::new(Field::new("magic", DataType::Int8, false)),
Arc::new(Field::new("leadership", DataType::Int8, false)),
Arc::new(Field::new("wisdom", DataType::Int8, false)),
];
let stats = StructArray::new(
stats_fields.into(),
vec![
Arc::new(strength),
Arc::new(magic),
Arc::new(leadership),
Arc::new(wisdom),
],
None,
);
let vectors = FixedSizeListArray::from_iter_primitive::<Float32Type, _, _>(
rows.iter()
.map(|row| Some(row.vector.iter().copied().map(Some).collect::<Vec<_>>())),
4,
);
let batch = RecordBatch::try_new(
schema.clone(),
vec![
Arc::new(ids),
Arc::new(names),
Arc::new(roles),
Arc::new(descriptions),
Arc::new(stats),
Arc::new(vectors),
],
)
.unwrap();
Box::new(RecordBatchIterator::new(
vec![Ok(batch)].into_iter(),
schema,
))
}
// --8<-- [end:quickstart_define_struct]
#[tokio::main]
async fn main() {
let temp_dir = tempfile::tempdir().unwrap();
let uri = temp_dir.path().to_str().unwrap();
let db = connect(uri).execute().await.unwrap();
// --8<-- [start:quickstart_data]
let data = vec![
Character {
id: "1".to_string(),
name: "King Arthur".to_string(),
role: "King".to_string(),
description: "Leader of Camelot and wielder of Excalibur.".to_string(),
stats: Stats {
strength: 4,
magic: 1,
leadership: 5,
wisdom: 4,
},
vector: [0.7, 0.1, 0.9, 0.7],
},
Character {
id: "2".to_string(),
name: "Merlin".to_string(),
role: "Wizard".to_string(),
description: "Advisor and prophet with deep magical knowledge.".to_string(),
stats: Stats {
strength: 2,
magic: 5,
leadership: 4,
wisdom: 5,
},
vector: [0.2, 0.9, 0.4, 0.9],
},
Character {
id: "3".to_string(),
name: "Sir Lancelot".to_string(),
role: "Knight".to_string(),
description: "Legendary knight known for courage and combat skill.".to_string(),
stats: Stats {
strength: 5,
magic: 1,
leadership: 3,
wisdom: 3,
},
vector: [0.9, 0.1, 0.5, 0.4],
},
];
// --8<-- [end:quickstart_data]
// --8<-- [start:quickstart_create_table]
use lancedb::database::CreateTableMode;
let schema = characters_schema();
let table = db
.create_table("characters", characters_to_reader(schema.clone(), &data))
.mode(CreateTableMode::Overwrite)
.execute()
.await
.unwrap();
// --8<-- [end:quickstart_create_table]
assert_eq!(table.count_rows(None).await.unwrap(), 3);
// --8<-- [start:quickstart_add_data]
let more_data = vec![Character {
id: "4".to_string(),
name: "Morgana".to_string(),
role: "Sorceress".to_string(),
description: "Powerful sorceress of Avalon.".to_string(),
stats: Stats {
strength: 2,
magic: 5,
leadership: 4,
wisdom: 4,
},
vector: [0.3, 0.9, 0.6, 0.8],
}];
table
.add(characters_to_reader(schema.clone(), &more_data))
.execute()
.await
.unwrap();
// --8<-- [end:quickstart_add_data]
assert_eq!(table.count_rows(None).await.unwrap(), 4);
// --8<-- [start:quickstart_vector_search_1]
use lancedb::arrow::IntoPolars;
use lancedb::query::{ExecutableQuery, QueryBase, Select};
// Search for examples similar to a "wise magical advisor"
let query_vector = [0.2, 0.8, 0.4, 0.9];
let result = table
.query()
.nearest_to(&query_vector)
.unwrap()
.select(Select::Columns(vec![
"name".to_string(),
"role".to_string(),
"description".to_string(),
"_distance".to_string(),
]))
.limit(2)
.execute()
.await
.unwrap()
.into_polars()
.await
.unwrap();
println!("{result:?}");
// --8<-- [end:quickstart_vector_search_1]
let name_col = result.column("name").unwrap().str().unwrap();
assert_eq!(name_col.get(0).unwrap(), "Merlin");
assert_eq!(name_col.get(1).unwrap(), "Morgana");
// --8<-- [start:quickstart_curate_with_metadata]
let curated = table
.query()
.nearest_to(&query_vector)
.unwrap()
.only_if("stats.magic >= 4")
.select(Select::Columns(vec![
"name".to_string(),
"role".to_string(),
"description".to_string(),
"_distance".to_string(),
]))
.limit(2)
.execute()
.await
.unwrap()
.into_polars()
.await
.unwrap();
println!("{curated:?}");
// --8<-- [end:quickstart_curate_with_metadata]
let curated_name_col = curated.column("name").unwrap().str().unwrap();
assert_eq!(curated_name_col.get(0).unwrap(), "Merlin");
assert_eq!(curated_name_col.get(1).unwrap(), "Morgana");
// --8<-- [start:quickstart_output_array]
let result = table
.query()
.nearest_to(&query_vector)
.unwrap()
.select(Select::Columns(vec![
"name".to_string(),
"role".to_string(),
"description".to_string(),
"_distance".to_string(),
]))
.limit(2)
.execute()
.await
.unwrap()
.into_polars()
.await
.unwrap();
println!("{result:?}");
// --8<-- [end:quickstart_output_array]
let name_col = result.column("name").unwrap().str().unwrap();
assert_eq!(name_col.get(0).unwrap(), "Merlin");
// --8<-- [start:quickstart_add_feature]
table
.add_columns(
NewColumnTransform::SqlExpressions(vec![(
"power_score".to_string(),
"cast(((stats.strength + stats.magic + stats.leadership + stats.wisdom) / 4.0) as float)"
.to_string(),
)]),
None,
)
.await
.unwrap();
// --8<-- [end:quickstart_add_feature]
// --8<-- [start:quickstart_query_feature]
let features = table
.query()
.select(Select::Columns(vec![
"name".to_string(),
"role".to_string(),
"power_score".to_string(),
]))
.execute()
.await
.unwrap()
.into_polars()
.await
.unwrap();
println!("{features:?}");
// --8<-- [end:quickstart_query_feature]
assert_eq!(features.column("power_score").unwrap().len(), 4);
// What the quickstart's download step leaves in an application's directory.
let app = tempfile::tempdir().unwrap();
std::fs::create_dir(app.path().join("data")).unwrap();
std::fs::copy(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("../../web/static/assets/images/quickstart/sir-lancelot.jpg"),
app.path().join("data/sir-lancelot.jpg"),
)
.unwrap();
std::env::set_current_dir(app.path()).unwrap();
// --8<-- [start:quickstart_multimodal_bytes]
use lancedb::arrow::arrow_array::BinaryArray;
let image_bytes = std::fs::read("data/sir-lancelot.jpg").unwrap();
let image_schema = Arc::new(Schema::new(vec![
Field::new("id", DataType::LargeUtf8, false),
Field::new("description", DataType::LargeUtf8, false),
Field::new("image", DataType::Binary, false),
Field::new(
"vector",
DataType::FixedSizeList(Arc::new(Field::new("item", DataType::Float32, true)), 4),
false,
),
]));
let image_vectors = [[0.9_f32, 0.1, 0.5, 0.4]];
let image_batch = RecordBatch::try_new(
image_schema.clone(),
vec![
Arc::new(LargeStringArray::from_iter_values(["lancelot"])),
Arc::new(LargeStringArray::from_iter_values([
"Portrait of Sir Lancelot",
])),
Arc::new(BinaryArray::from_iter_values([image_bytes.as_slice()])),
Arc::new(
FixedSizeListArray::from_iter_primitive::<Float32Type, _, _>(
image_vectors
.iter()
.map(|vector| Some(vector.iter().copied().map(Some).collect::<Vec<_>>())),
4,
),
),
],
)
.unwrap();
let image_reader: Box<dyn RecordBatchReader + Send> = Box::new(RecordBatchIterator::new(
vec![Ok(image_batch)].into_iter(),
image_schema,
));
let multimodal_table = db
.create_table("character_images", image_reader)
.mode(CreateTableMode::Overwrite)
.execute()
.await
.unwrap();
// --8<-- [end:quickstart_multimodal_bytes]
assert_eq!(multimodal_table.count_rows(None).await.unwrap(), 1);
}