lancedb/docs/src/migration.md

Rust-backed Client Migration Guide

In an effort to ensure all clients have the same set of capabilities we have migrated the Python and Node clients onto a common Rust base library. In Python, both the synchronous and asynchronous clients are based on this implementation. In Node, the new client is available as @lancedb/lancedb, which replaces the existing vectordb package.

This guide describes the differences between the two Node APIs and will hopefully assist users that would like to migrate to the new API.

TypeScript/JavaScript

For JS/TS users, we offer a brand new SDK @lancedb/lancedb

We tried to keep the API as similar as possible to the previous version, but there are a few small changes. Here are the most important ones:

Creating Tables

CreateTableOptions.writeOptions.writeMode has been replaced with CreateTableOptions.mode

=== "vectordb (deprecated)"

```ts
db.createTable(tableName, data, { writeMode: lancedb.WriteMode.Overwrite });
```

=== "@lancedb/lancedb"

```ts
db.createTable(tableName, data, { mode: "overwrite" })
```

Changes to Table APIs

Previously Table.schema was a property. Now it is an async method.

Creating Indices

The Table.createIndex method is now used for creating both vector indices and scalar indices. It currently requires a column name to be specified (the column to index). Vector index defaults are now smarter and scale better with the size of the data.

=== "vectordb (deprecated)"

```ts
await tbl.createIndex({
  column: "vector", // default
  type: "ivf_pq",
  num_partitions: 2,
  num_sub_vectors: 2,
});
```

=== "@lancedb/lancedb"

```ts
await table.createIndex("vector", {
  config: lancedb.Index.ivfPq({
    numPartitions: 2,
    numSubVectors: 2,
  }),
});
```

Embedding Functions

The embedding API has been completely reworked, and it now more closely resembles the Python API, including the new embedding registry:

=== "vectordb (deprecated)"

```ts

const embeddingFunction = new lancedb.OpenAIEmbeddingFunction('text', API_KEY)
const data = [
    { id: 1, text: 'Black T-Shirt', price: 10 },
    { id: 2, text: 'Leather Jacket', price: 50 }
]
const table = await db.createTable('vectors', data, embeddingFunction)
```

=== "@lancedb/lancedb"

```ts
import * as lancedb from "@lancedb/lancedb";
import * as arrow from "apache-arrow";
import { LanceSchema, getRegistry } from "@lancedb/lancedb/embedding";

const func = getRegistry().get("openai").create({apiKey: API_KEY});

const data = [
    { id: 1, text: 'Black T-Shirt', price: 10 },
    { id: 2, text: 'Leather Jacket', price: 50 }
]

const table = await db.createTable('vectors', data, {
    embeddingFunction: {
        sourceColumn: "text",
        function: func,
    }
})

```

You can also use a schema driven approach, which parallels the Pydantic integration in our Python SDK:

const func = getRegistry().get("openai").create({apiKey: API_KEY});

const data = [
    { id: 1, text: 'Black T-Shirt', price: 10 },
    { id: 2, text: 'Leather Jacket', price: 50 }
]
const schema = LanceSchema({
    id: new arrow.Int32(),
    text: func.sourceField(new arrow.Utf8()),
    price: new arrow.Float64(),
    vector: func.vectorField()
})

const table = await db.createTable('vectors', data, {schema})