Files
lancedb/docs
Drew 6702e3fec1 feat(node): add blob v2 fetch and field helpers (#4155)
this PR blob v2 field helpers and reads to the Node SDK.

`blob()` marks a field as blob v2 and lets you set the storage
thresholds. Inputs can be bytes, a URI, or a data/uri struct.

Queries return descriptors. `fetchBlobs()` reads the bytes by row ID,
and `fetchBlobFiles()` gives you lazy handles for full or range reads.
`blobColumns()` lists the blob fields, including nested ones.

Fetch uses the table’s current checkout. It preserves order, duplicates,
and nulls. Holding row IDs across compaction still requires stable row
IDs.

```javascript
const db = await connect("./data");
const video = await readFile("clip.mp4");
const table = await db.createTable(
  "videos",
  [{ id: 1n, video }],
  {
    schema: new Schema([
      new Field("id", new Int64()),
      blob("video"),
    ]),
  },
);
const rows = await table.query().select(["id"]).withRowId().toArray();
const rowIds = rows.map((row) => row._rowid as bigint);
const bytes = await table.fetchBlobs("video", rowIds);
const [handle] = await table.fetchBlobFiles("video", rowIds);
const header = await handle!.readRange(0n, 65536n);

```

### Testing

- cover input validation, thresholds, nested fields, fetch ordering,
nulls, and range reads.
2026-09-11 14:46:27 -07:00
..
2026-09-09 15:33:04 +08:00

LanceDB Documentation

LanceDB docs are available at docs.lancedb.com.

The SDK docs are built and deployed automatically by Github Actions whenever a commit is pushed to the main branch. So it is possible for the docs to show unreleased features.

Building the docs

Setup

  1. Install LanceDB Python. See setup in Python contributing guide. Run make develop to install the Python package.
  2. Install documentation dependencies. From LanceDB repo root: pip install -r docs/requirements.txt

Preview the docs

cd docs
mkdocs serve

If you want to just generate the HTML files:

PYTHONPATH=. mkdocs build -f docs/mkdocs.yml

If successful, you should see a docs/site directory that you can verify locally.

Adding examples

To make sure examples are correct, we put examples in test files so they can be run as part of our test suites.

You can see the tests are at:

  • Python: python/python/tests/docs
  • Typescript: nodejs/examples/

Checking python examples

cd python
pytest -vv python/tests/docs

Checking typescript examples

The examples depend on @lancedb/lancedb at file:../dist, so the package must be built before running the tests. This uses pnpm; see the Typescript contributing guide for the toolchain setup.

pushd nodejs
pnpm install
pnpm build
popd

Then you can run the examples by going to the nodejs/examples directory, which is a separate pnpm package with its own lockfile:

pushd nodejs/examples
pnpm install
pnpm test
popd

API documentation

Python

The Python API documentation is organized based on the file docs/src/python/python.md. We manually add entries there so we can control the organization of the reference page. However, this means any new types must be manually added to the file. No additional steps are needed to generate the API documentation.

Typescript

The typescript API documentation is generated from the typescript source code using typedoc.

When new APIs are added, you must manually re-run the typedoc command to update the API documentation. The new files should be checked into the repository.

pushd nodejs
# `pnpm docs` would invoke pnpm's built-in `docs` command, not the script.
pnpm run docs
popd