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vectordb / Exports / LocalTable

Class: LocalTable\<T>

A LanceDB Table is the collection of Records. Each Record has one or more vector fields.

Type parameters

Name Type
T number[]

Implements

Table of contents

Constructors

Properties

Accessors

Methods

Constructors

constructor

new LocalTable\<T>(tbl, name, options)

Type parameters

Name Type
T number[]

Parameters

Name Type
tbl any
name string
options ConnectionOptions

Defined in

index.ts:861

new LocalTable\<T>(tbl, name, options, embeddings)

Type parameters

Name Type
T number[]

Parameters

Name Type Description
tbl any
name string
options ConnectionOptions
embeddings EmbeddingFunction\<T> An embedding function to use when interacting with this table

Defined in

index.ts:868

Properties

_embeddings

Private Optional Readonly _embeddings: EmbeddingFunction\<T>

Defined in

index.ts:858


_isElectron

Private Readonly _isElectron: boolean

Defined in

index.ts:857


_name

Private Readonly _name: string

Defined in

index.ts:856


_options

Private Readonly _options: () => ConnectionOptions

Type declaration

▸ (): ConnectionOptions

Returns

ConnectionOptions

Defined in

index.ts:859


_tbl

Private _tbl: any

Defined in

index.ts:855


where

where: (value: string) => Query\<T>

Type declaration

▸ (value): Query\<T>

Creates a filter query to find all rows matching the specified criteria

Parameters
Name Type Description
value string The filter criteria (like SQL where clause syntax)
Returns

Query\<T>

Defined in

index.ts:907

Accessors

name

get name(): string

Returns

string

Implementation of

Table.name

Defined in

index.ts:887


schema

get schema(): Promise\<Schema\<any>>

Returns

Promise\<Schema\<any>>

Implementation of

Table.schema

Defined in

index.ts:1127

Methods

add

add(data): Promise\<number>

Insert records into this Table.

Parameters

Name Type Description
data Table\<any> | Record\<string, unknown>[] Records to be inserted into the Table

Returns

Promise\<number>

The number of rows added to the table

Implementation of

Table.add

Defined in

index.ts:915


addColumns

addColumns(newColumnTransforms): Promise\<void>

Add new columns with defined values.

Parameters

Name Type Description
newColumnTransforms { name: string ; valueSql: string }[] pairs of column names and the SQL expression to use to calculate the value of the new column. These expressions will be evaluated for each row in the table, and can reference existing columns in the table.

Returns

Promise\<void>

Implementation of

Table.addColumns

Defined in

index.ts:1151


alterColumns

alterColumns(columnAlterations): Promise\<void>

Alter the name or nullability of columns.

Parameters

Name Type Description
columnAlterations ColumnAlteration[] One or more alterations to apply to columns.

Returns

Promise\<void>

Implementation of

Table.alterColumns

Defined in

index.ts:1155


checkElectron

Private checkElectron(): boolean

Returns

boolean

Defined in

index.ts:1139


cleanupOldVersions

cleanupOldVersions(olderThan?, deleteUnverified?): Promise\<CleanupStats>

Clean up old versions of the table, freeing disk space.

Parameters

Name Type Description
olderThan? number The minimum age in minutes of the versions to delete. If not provided, defaults to two weeks.
deleteUnverified? boolean Because they may be part of an in-progress transaction, uncommitted files newer than 7 days old are not deleted by default. This means that failed transactions can leave around data that takes up disk space for up to 7 days. You can override this safety mechanism by setting this option to true, only if you promise there are no in progress writes while you run this operation. Failure to uphold this promise can lead to corrupted tables.

Returns

Promise\<CleanupStats>

Defined in

index.ts:1086


compactFiles

compactFiles(options?): Promise\<CompactionMetrics>

Run the compaction process on the table.

This can be run after making several small appends to optimize the table for faster reads.

Parameters

Name Type Description
options? CompactionOptions Advanced options configuring compaction. In most cases, you can omit this arguments, as the default options are sensible for most tables.

Returns

Promise\<CompactionMetrics>

Metrics about the compaction operation.

Defined in

index.ts:1109


countRows

countRows(filter?): Promise\<number>

Returns the number of rows in this table.

Parameters

Name Type
filter? string

Returns

Promise\<number>

Implementation of

Table.countRows

Defined in

index.ts:987


createIndex

createIndex(indexParams): Promise\<any>

Create an ANN index on this Table vector index.

Parameters

Name Type Description
indexParams IvfPQIndexConfig The parameters of this Index,

Returns

Promise\<any>

See

VectorIndexParams.

Implementation of

Table.createIndex

Defined in

index.ts:969


createScalarIndex

createScalarIndex(column, replace?): Promise\<void>

Create a scalar index on this Table for the given column

Parameters

Name Type Description
column string The column to index
replace? boolean If false, fail if an index already exists on the column it is always set to true for remote connections Scalar indices, like vector indices, can be used to speed up scans. A scalar index can speed up scans that contain filter expressions on the indexed column. For example, the following scan will be faster if the column my_col has a scalar index: ts const con = await lancedb.connect('./.lancedb'); const table = await con.openTable('images'); const results = await table.where('my_col = 7').execute(); Scalar indices can also speed up scans containing a vector search and a prefilter: ts const con = await lancedb.connect('././lancedb'); const table = await con.openTable('images'); const results = await table.search([1.0, 2.0]).where('my_col != 7').prefilter(true); Scalar indices can only speed up scans for basic filters using equality, comparison, range (e.g. my_col BETWEEN 0 AND 100), and set membership (e.g. my_col IN (0, 1, 2)) Scalar indices can be used if the filter contains multiple indexed columns and the filter criteria are AND'd or OR'd together (e.g. my_col < 0 AND other_col> 100) Scalar indices may be used if the filter contains non-indexed columns but, depending on the structure of the filter, they may not be usable. For example, if the column not_indexed does not have a scalar index then the filter my_col = 0 OR not_indexed = 1 will not be able to use any scalar index on my_col.

Returns

Promise\<void>

Examples

const con = await lancedb.connect('././lancedb')
const table = await con.openTable('images')
await table.createScalarIndex('my_col')

Implementation of

Table.createScalarIndex

Defined in

index.ts:977


delete

delete(filter): Promise\<void>

Delete rows from this table.

Parameters

Name Type Description
filter string A filter in the same format used by a sql WHERE clause.

Returns

Promise\<void>

Implementation of

Table.delete

Defined in

index.ts:996


dropColumns

dropColumns(columnNames): Promise\<void>

Drop one or more columns from the dataset

This is a metadata-only operation and does not remove the data from the underlying storage. In order to remove the data, you must subsequently call compact_files to rewrite the data without the removed columns and then call cleanup_files to remove the old files.

Parameters

Name Type Description
columnNames string[] The names of the columns to drop. These can be nested column references (e.g. "a.b.c") or top-level column names (e.g. "a").

Returns

Promise\<void>

Implementation of

Table.dropColumns

Defined in

index.ts:1159


filter

filter(value): Query\<T>

Creates a filter query to find all rows matching the specified criteria

Parameters

Name Type Description
value string The filter criteria (like SQL where clause syntax)

Returns

Query\<T>

Implementation of

Table.filter

Defined in

index.ts:903


getSchema

Private getSchema(): Promise\<Schema\<any>>

Returns

Promise\<Schema\<any>>

Defined in

index.ts:1132


indexStats

indexStats(indexUuid): Promise\<IndexStats>

Get statistics about an index.

Parameters

Name Type
indexUuid string

Returns

Promise\<IndexStats>

Implementation of

Table.indexStats

Defined in

index.ts:1123


listIndices

listIndices(): Promise\<VectorIndex[]>

List the indicies on this table.

Returns

Promise\<VectorIndex[]>

Implementation of

Table.listIndices

Defined in

index.ts:1119


mergeInsert

mergeInsert(on, data, args): Promise\<void>

Runs a "merge insert" operation on the table

This operation can add rows, update rows, and remove rows all in a single transaction. It is a very generic tool that can be used to create behaviors like "insert if not exists", "update or insert (i.e. upsert)", or even replace a portion of existing data with new data (e.g. replace all data where month="january")

The merge insert operation works by combining new data from a source table with existing data in a target table by using a join. There are three categories of records.

"Matched" records are records that exist in both the source table and the target table. "Not matched" records exist only in the source table (e.g. these are new data) "Not matched by source" records exist only in the target table (this is old data)

The MergeInsertArgs can be used to customize what should happen for each category of data.

Please note that the data may appear to be reordered as part of this operation. This is because updated rows will be deleted from the dataset and then reinserted at the end with the new values.

Parameters

Name Type Description
on string a column to join on. This is how records from the source table and target table are matched.
data Table\<any> | Record\<string, unknown>[] the new data to insert
args MergeInsertArgs parameters controlling how the operation should behave

Returns

Promise\<void>

Implementation of

Table.mergeInsert

Defined in

index.ts:1031


overwrite

overwrite(data): Promise\<number>

Insert records into this Table, replacing its contents.

Parameters

Name Type Description
data Table\<any> | Record\<string, unknown>[] Records to be inserted into the Table

Returns

Promise\<number>

The number of rows added to the table

Implementation of

Table.overwrite

Defined in

index.ts:943


search(query): Query\<T>

Creates a search query to find the nearest neighbors of the given search term

Parameters

Name Type Description
query T The query search term

Returns

Query\<T>

Implementation of

Table.search

Defined in

index.ts:895


update

update(args): Promise\<void>

Update rows in this table.

Parameters

Name Type Description
args UpdateArgs | UpdateSqlArgs see UpdateArgs and UpdateSqlArgs for more details

Returns

Promise\<void>

Implementation of

Table.update

Defined in

index.ts:1009


withMiddleware

withMiddleware(middleware): Table\<T>

Instrument the behavior of this Table with middleware.

The middleware will be called in the order they are added.

Currently this functionality is only supported for remote tables.

Parameters

Name Type
middleware HttpMiddleware

Returns

Table\<T>

  • this Table instrumented by the passed middleware

Implementation of

Table.withMiddleware

Defined in

index.ts:1163