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\<T>
Table of contents
Constructors
Properties
Accessors
Methods
- add
- addColumns
- alterColumns
- checkElectron
- cleanupOldVersions
- compactFiles
- countRows
- createIndex
- createScalarIndex
- delete
- dropColumns
- dropIndex
- filter
- getSchema
- indexStats
- listIndices
- mergeInsert
- overwrite
- search
- update
- withMiddleware
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
•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
Properties
_embeddings
•PrivateOptionalReadonly_embeddings:EmbeddingFunction\<T>
Defined in
_isElectron
•PrivateReadonly_isElectron:boolean
Defined in
_name
•PrivateReadonly_name:string
Defined in
_options
•PrivateReadonly_options: () =>ConnectionOptions
Type declaration
▸ ():ConnectionOptions
Returns
Defined in
_tbl
•Private_tbl:any
Defined in
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
Accessors
name
•getname():string
Returns
string
Implementation of
Defined in
schema
•getschema():Promise\<Schema\<any>>
Returns
Promise\<Schema\<any>>
Implementation of
Defined in
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
Defined in
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
Defined in
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
Defined in
checkElectron
▸PrivatecheckElectron():boolean
Returns
boolean
Defined in
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 totrue, 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
compactFiles
▸compactFiles(options?):Promise\<CompactionMetrics>
Run the compaction process on the table.
This can be run after making several small appends to optimize the tablefor 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
countRows
▸countRows(filter?):Promise\<number>
Returns the number of rows in this table.
Parameters
| Name | Type |
|---|---|
filter? | string |
Returns
Promise\<number>
Implementation of
Defined in
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
Defined in
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 columnmy_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 columnnot_indexed does not have a scalar index then the filtermy_col = 0 OR not_indexed = 1 will not be able to use any scalar index onmy_col. |
Returns
Promise\<void>
Examples
constcon=awaitlancedb.connect('././lancedb')consttable=awaitcon.openTable('images')awaittable.createScalarIndex('my_col')Implementation of
Defined in
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
Defined in
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 theunderlying storage. In order to remove the data, you must subsequentlycallcompact_files to rewrite the data without the removed columns andthen callcleanup_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
Defined in
dropIndex
▸dropIndex(indexName):Promise\<void>
Drop an index from the table
Parameters
| Name | Type | Description |
|---|---|---|
indexName | string | The name of the index to drop |
Returns
Promise\<void>
Implementation of
Defined in
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
Defined in
getSchema
▸PrivategetSchema():Promise\<Schema\<any>>
Returns
Promise\<Schema\<any>>
Defined in
indexStats
▸indexStats(indexName):Promise\<IndexStats>
Get statistics about an index.
Parameters
| Name | Type |
|---|---|
indexName | string |
Returns
Promise\<IndexStats>
Implementation of
Defined in
listIndices
▸listIndices():Promise\<VectorIndex[]>
List the indicies on this table.
Returns
Promise\<VectorIndex[]>
Implementation of
Defined in
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 singletransaction. It is a very generic tool that can be used to createbehaviors like "insert if not exists", "update or insert (i.e. upsert)",or even replace a portion of existing data with new data (e.g. replaceall data where month="january")
The merge insert operation works by combining new data from asource table with existing data in atarget table by using ajoin. There are three categories of records.
"Matched" records are records that exist in both the source table andthe target table. "Not matched" records exist only in the source table(e.g. these are new data) "Not matched by source" records exist onlyin the target table (this is old data)
The MergeInsertArgs can be used to customize what should happen foreach category of data.
Please note that the data may appear to be reordered as part of thisoperation. This is because updated rows will be deleted from thedataset 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
Defined in
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
Defined in
search
▸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
Defined in
update
▸update(args):Promise\<void>
Update rows in this table.
Parameters
| Name | Type | Description |
|---|---|---|
args | UpdateArgs |UpdateSqlArgs | seeUpdateArgs andUpdateSqlArgs for more details |
Returns
Promise\<void>
Implementation of
Defined in
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