`langchain_community.vectorstores.cassandra`.Cassandra¶

class langchain_community.vectorstores.cassandra.Cassandra(embedding: Embeddings, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = '', ttl_seconds: Optional[int] = None, *, body_index_options: Optional[List[Tuple[str, Any]]] = None, setup_mode: SetupMode = SetupMode.SYNC, metadata_indexing: Union[Tuple[str, Iterable[str]], str] = 'all')[source]¶

Apache Cassandra(R) for vector-store workloads.

To use it, you need a recent installation of the cassio library and a Cassandra cluster / Astra DB instance supporting vector capabilities.

Visit the cassio.org website for extensive quickstarts and code examples.

Example

from langchain_community.vectorstores import Cassandra
from langchain_openai import OpenAIEmbeddings

embeddings = OpenAIEmbeddings()
session = ...             # create your Cassandra session object
keyspace = 'my_keyspace'  # the keyspace should exist already
table_name = 'my_vector_store'
vectorstore = Cassandra(embeddings, session, keyspace, table_name)

Parameters

embedding (Embeddings) – Embedding function to use.
session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.
keyspace (Optional[str]) – Cassandra keyspace. If not provided, it is resolved from cassio.
table_name (str) – Cassandra table (required).
ttl_seconds (Optional[int]) – Optional time-to-live for the added texts.
body_index_options (Optional[List[Tuple[str, Any]]]) – Optional options used to create the body index. Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
setup_mode (SetupMode) – mode used to create the Cassandra table (SYNC, ASYNC or OFF).
metadata_indexing (Union[Tuple[str, Iterable[str]], str]) –
Optional specification of a metadata indexing policy, i.e. to fine-tune which of the metadata fields are indexed. It can be a string (“all” or “none”), or a 2-tuple. The following means that all fields except ‘f1’, ‘f2’ … are NOT indexed:

metadata_indexing=(“allowlist”, [“f1”, “f2”, …])

The following means all fields EXCEPT ‘g1’, ‘g2’, … are indexed:
metadata_indexing(“denylist”, [“g1”, “g2”, …])

The default is to index every metadata field. Note: if you plan to have massive unique text metadata entries, consider not indexing them for performance (and to overcome max-length limitations).

Attributes

embeddings

Access the query embedding object if available.

Methods

`__init__`(embedding[, session, keyspace, ...])	Apache Cassandra(R) for vector-store workloads.
`aadd_documents`(documents, **kwargs)	Async run more documents through the embeddings and add to the vectorstore.
`aadd_texts`(texts[, metadatas, ids, ...])	Run more texts through the embeddings and add to the vectorstore.
`aclear`()	Empty the table.
`add_documents`(documents, **kwargs)	Add or update documents in the vectorstore.
`add_texts`(texts[, metadatas, ids, ...])	Run more texts through the embeddings and add to the vectorstore.
`adelete`([ids])	Delete by vector IDs.
`adelete_by_document_id`(document_id)	Delete by document ID.
`adelete_collection`()	Just an alias for aclear (to better align with other VectorStore implementations).
`afrom_documents`(documents, embedding, *[, ...])	Create a Cassandra vectorstore from a document list.
`afrom_texts`(texts, embedding[, metadatas, ...])	Create a Cassandra vectorstore from raw texts.
`aget_by_ids`(ids, /)	Async get documents by their IDs.
`amax_marginal_relevance_search`(query[, k, ...])	Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param query: Text to look up documents similar to. :param k: Number of Documents to return. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm. :param lambda_mult: Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5. :param filter: Filter on the metadata to apply. :param body_search: Document textual search terms to apply. Only supported by Astra DB at the moment.
`amax_marginal_relevance_search_by_vector`(...)	Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param embedding: Embedding to look up documents similar to. :param k: Number of Documents to return. Defaults to 4. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm. Defaults to 20. :param lambda_mult: Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5. :param filter: Filter on the metadata to apply. :param body_search: Document textual search terms to apply. Only supported by Astra DB at the moment.
`as_retriever`([search_type, search_kwargs, ...])	Return VectorStoreRetriever initialized from this VectorStore.
`asearch`(query, search_type, **kwargs)	Async return docs most similar to query using a specified search type.
`asimilarity_search`(query[, k, filter, ...])	Return docs most similar to query.
`asimilarity_search_by_vector`(embedding[, k, ...])	Return docs most similar to embedding vector.
`asimilarity_search_with_relevance_scores`(query)	Async return docs and relevance scores in the range [0, 1].
`asimilarity_search_with_score`(query[, k, ...])	Return docs most similar to query.
`asimilarity_search_with_score_by_vector`(...)	Return docs most similar to embedding vector.
`asimilarity_search_with_score_id`(query[, k, ...])	Return docs most similar to query.
`asimilarity_search_with_score_id_by_vector`(...)	Return docs most similar to embedding vector.
`astreaming_upsert`(items, /, batch_size, **kwargs)	[Beta] Upsert documents in a streaming fashion.
`aupsert`(items, /, **kwargs)	[Beta] Add or update documents in the vectorstore.
`clear`()	Empty the table.
`delete`([ids])	Delete by vector IDs.
`delete_by_document_id`(document_id)	Delete by document ID.
`delete_collection`()	Just an alias for clear (to better align with other VectorStore implementations).
`from_documents`(documents, embedding, *[, ...])	Create a Cassandra vectorstore from a document list.
`from_texts`(texts, embedding[, metadatas, ...])	Create a Cassandra vectorstore from raw texts.
`get_by_ids`(ids, /)	Get documents by their IDs.
`max_marginal_relevance_search`(query[, k, ...])	Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param query: Text to look up documents similar to. :param k: Number of Documents to return. Defaults to 4. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm. Defaults to 20. :param lambda_mult: Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5. :param filter: Filter on the metadata to apply. :param body_search: Document textual search terms to apply. Only supported by Astra DB at the moment.
`max_marginal_relevance_search_by_vector`(...)	Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param embedding: Embedding to look up documents similar to. :param k: Number of Documents to return. Defaults to 4. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm. Defaults to 20. :param lambda_mult: Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5. :param filter: Filter on the metadata to apply. :param body_search: Document textual search terms to apply. Only supported by Astra DB at the moment.
`search`(query, search_type, **kwargs)	Return docs most similar to query using a specified search type.
`similarity_search`(query[, k, filter, ...])	Return docs most similar to query.
`similarity_search_by_vector`(embedding[, k, ...])	Return docs most similar to embedding vector.
`similarity_search_with_relevance_scores`(query)	Return docs and relevance scores in the range [0, 1].
`similarity_search_with_score`(query[, k, ...])	Return docs most similar to query.
`similarity_search_with_score_by_vector`(embedding)	Return docs most similar to embedding vector.
`similarity_search_with_score_id`(query[, k, ...])	Return docs most similar to query.
`similarity_search_with_score_id_by_vector`(...)	Return docs most similar to embedding vector.
`streaming_upsert`(items, /, batch_size, **kwargs)	[Beta] Upsert documents in a streaming fashion.
`upsert`(items, /, **kwargs)	[Beta] Add or update documents in the vectorstore.

__init__(embedding: Embeddings, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = '', ttl_seconds: Optional[int] = None, *, body_index_options: Optional[List[Tuple[str, Any]]] = None, setup_mode: SetupMode = SetupMode.SYNC, metadata_indexing: Union[Tuple[str, Iterable[str]], str] = 'all') → None[source]¶

Apache Cassandra(R) for vector-store workloads.

To use it, you need a recent installation of the cassio library and a Cassandra cluster / Astra DB instance supporting vector capabilities.

Visit the cassio.org website for extensive quickstarts and code examples.

Example

from langchain_community.vectorstores import Cassandra
from langchain_openai import OpenAIEmbeddings

embeddings = OpenAIEmbeddings()
session = ...             # create your Cassandra session object
keyspace = 'my_keyspace'  # the keyspace should exist already
table_name = 'my_vector_store'
vectorstore = Cassandra(embeddings, session, keyspace, table_name)

Parameters

embedding (Embeddings) – Embedding function to use.
session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.
keyspace (Optional[str]) – Cassandra keyspace. If not provided, it is resolved from cassio.
table_name (str) – Cassandra table (required).
ttl_seconds (Optional[int]) – Optional time-to-live for the added texts.
body_index_options (Optional[List[Tuple[str, Any]]]) – Optional options used to create the body index. Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
setup_mode (SetupMode) – mode used to create the Cassandra table (SYNC, ASYNC or OFF).
metadata_indexing (Union[Tuple[str, Iterable[str]], str]) –
Optional specification of a metadata indexing policy, i.e. to fine-tune which of the metadata fields are indexed. It can be a string (“all” or “none”), or a 2-tuple. The following means that all fields except ‘f1’, ‘f2’ … are NOT indexed:

metadata_indexing=(“allowlist”, [“f1”, “f2”, …])

The following means all fields EXCEPT ‘g1’, ‘g2’, … are indexed:
metadata_indexing(“denylist”, [“g1”, “g2”, …])

The default is to index every metadata field. Note: if you plan to have massive unique text metadata entries, consider not indexing them for performance (and to overcome max-length limitations).

Return type

None

async aadd_documents(documents: List[Document], **kwargs: Any) → List[str]¶

Async run more documents through the embeddings and add to the vectorstore.

Parameters

documents (List[Document]) – Documents to add to the vectorstore.
kwargs (Any) – Additional keyword arguments.

Returns

List of IDs of the added texts.

Raises

ValueError – If the number of IDs does not match the number of documents.

Return type

List[str]

async aadd_texts(texts: Iterable[str], metadatas: Optional[List[dict]] = None, ids: Optional[List[str]] = None, concurrency: int = 16, ttl_seconds: Optional[int] = None, **kwargs: Any) → List[str][source]¶

Run more texts through the embeddings and add to the vectorstore.

Parameters

texts (Iterable[str]) – Texts to add to the vectorstore.
metadatas (Optional[List[dict]]) – Optional list of metadatas.
ids (Optional[List[str]]) – Optional list of IDs.
concurrency (int) – Number of concurrent queries to the database. Defaults to 16.
ttl_seconds (Optional[int]) – Optional time-to-live for the added texts.
kwargs (Any) –

Returns

List of IDs of the added texts.

Return type

List[str]

async aclear() → None[source]¶

Empty the table.

Return type: None

add_documents(documents: List[Document], **kwargs: Any) → List[str]¶

Add or update documents in the vectorstore.

Parameters

documents (List[Document]) – Documents to add to the vectorstore.
kwargs (Any) – Additional keyword arguments. if kwargs contains ids and documents contain ids, the ids in the kwargs will receive precedence.

Returns

List of IDs of the added texts.

Raises

ValueError – If the number of ids does not match the number of documents.

Return type

List[str]

add_texts(texts: Iterable[str], metadatas: Optional[List[dict]] = None, ids: Optional[List[str]] = None, batch_size: int = 16, ttl_seconds: Optional[int] = None, **kwargs: Any) → List[str][source]¶

Run more texts through the embeddings and add to the vectorstore.

Parameters

texts (Iterable[str]) – Texts to add to the vectorstore.
metadatas (Optional[List[dict]]) – Optional list of metadatas.
ids (Optional[List[str]]) – Optional list of IDs.
batch_size (int) – Number of concurrent requests to send to the server.
ttl_seconds (Optional[int]) – Optional time-to-live for the added texts.
kwargs (Any) –

Returns

List of IDs of the added texts.

Return type

List[str]

async adelete(ids: Optional[List[str]] = None, **kwargs: Any) → Optional[bool][source]¶

Delete by vector IDs.

Parameters

ids (Optional[List[str]]) – List of ids to delete.
kwargs (Any) –

Returns

True if deletion is successful, False otherwise, None if not implemented.

Return type

Optional[bool]

async adelete_by_document_id(document_id: str) → None[source]¶

Delete by document ID.

Parameters: document_id (str) – the document ID to delete.
Return type: None

async adelete_collection() → None[source]¶

Just an alias for aclear (to better align with other VectorStore implementations).

Return type: None

async classmethod afrom_documents(documents: List[Document], embedding: Embeddings, *, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = '', ids: Optional[List[str]] = None, concurrency: int = 16, ttl_seconds: Optional[int] = None, body_index_options: Optional[List[Tuple[str, Any]]] = None, metadata_indexing: Union[Tuple[str, Iterable[str]], str] = 'all', **kwargs: Any) → CVST[source]¶

Create a Cassandra vectorstore from a document list.

Parameters

documents (List[Document]) – Documents to add to the vectorstore.
embedding (Embeddings) – Embedding function to use.
session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.
keyspace (Optional[str]) – Cassandra key space. If not provided, it is resolved from cassio.
table_name (str) – Cassandra table (required).
ids (Optional[List[str]]) – Optional list of IDs associated with the documents.
concurrency (int) – Number of concurrent queries to send to the database. Defaults to 16.
ttl_seconds (Optional[int]) – Optional time-to-live for the added documents.
body_index_options (Optional[List[Tuple[str, Any]]]) – Optional options used to create the body index. Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
metadata_indexing (Union[Tuple[str, Iterable[str]], str]) –
kwargs (Any) –

Returns

a Cassandra vectorstore.

Return type

CVST

async classmethod afrom_texts(texts: List[str], embedding: Embeddings, metadatas: Optional[List[dict]] = None, *, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = '', ids: Optional[List[str]] = None, concurrency: int = 16, ttl_seconds: Optional[int] = None, body_index_options: Optional[List[Tuple[str, Any]]] = None, metadata_indexing: Union[Tuple[str, Iterable[str]], str] = 'all', **kwargs: Any) → CVST[source]¶

Create a Cassandra vectorstore from raw texts.

Parameters

texts (List[str]) – Texts to add to the vectorstore.
embedding (Embeddings) – Embedding function to use.
metadatas (Optional[List[dict]]) – Optional list of metadatas associated with the texts.
session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.
keyspace (Optional[str]) – Cassandra key space. If not provided, it is resolved from cassio.
table_name (str) – Cassandra table (required).
ids (Optional[List[str]]) – Optional list of IDs associated with the texts.
concurrency (int) – Number of concurrent queries to send to the database. Defaults to 16.
ttl_seconds (Optional[int]) – Optional time-to-live for the added texts.
body_index_options (Optional[List[Tuple[str, Any]]]) – Optional options used to create the body index. Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
metadata_indexing (Union[Tuple[str, Iterable[str]], str]) –
kwargs (Any) –

Returns

a Cassandra vectorstore.

Return type

CVST

async aget_by_ids(ids: Sequence[str], /) → List[Document]¶

Async get documents by their IDs.

The returned documents are expected to have the ID field set to the ID of the document in the vector store.

Fewer documents may be returned than requested if some IDs are not found or if there are duplicated IDs.

Users should not assume that the order of the returned documents matches the order of the input IDs. Instead, users should rely on the ID field of the returned documents.

This method should NOT raise exceptions if no documents are found for some IDs.

Parameters: ids (Sequence[str]) – List of ids to retrieve.
Returns: List of Documents.
Return type: List[Document]

New in version 0.2.11.

async amax_marginal_relevance_search(query: str, k: int = 4, fetch_k: int = 20, lambda_mult: float = 0.5, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param query: Text to look up documents similar to. :param k: Number of Documents to return. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm. :param lambda_mult: Number between 0 and 1 that determines the degree

of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5.

Parameters

filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
query (str) –
k (int) –
fetch_k (int) –
lambda_mult (float) –
kwargs (Any) –

Returns

List of Documents selected by maximal marginal relevance.

Return type

List[Document]

async amax_marginal_relevance_search_by_vector(embedding: List[float], k: int = 4, fetch_k: int = 20, lambda_mult: float = 0.5, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param embedding: Embedding to look up documents similar to. :param k: Number of Documents to return. Defaults to 4. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm.

Defaults to 20.

Parameters

lambda_mult (float) – Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
embedding (List[float]) –
k (int) –
fetch_k (int) –
kwargs (Any) –

Returns

List of Documents selected by maximal marginal relevance.

Return type

List[Document]

as_retriever(search_type: str = 'similarity', search_kwargs: Optional[Dict[str, Any]] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) → VectorStoreRetriever[source]¶

Return VectorStoreRetriever initialized from this VectorStore.

Parameters

search_type (str) – Defines the type of search that the Retriever should perform. Can be “similarity” (default), “mmr”, or “similarity_score_threshold”.
search_kwargs (Optional[Dict[str, Any]]) –
Keyword arguments to pass to the search function. Can include things like:

k: Amount of documents to return (Default: 4) score_threshold: Minimum relevance threshold

for similarity_score_threshold

fetch_k: Amount of documents to pass to MMR algorithm (Default: 20) lambda_mult: Diversity of results returned by MMR;

1 for minimum diversity and 0 for maximum. (Default: 0.5)

filter: Filter by document metadata
tags (Optional[List[str]]) – List of tags associated with the retriever.
metadata (Optional[Dict[str, Any]]) – Metadata associated with the retriever.
kwargs (Any) – Other arguments passed to the VectorStoreRetriever init.

Returns

Retriever for VectorStore.

Return type

VectorStoreRetriever

Examples:

# Retrieve more documents with higher diversity
# Useful if your dataset has many similar documents
docsearch.as_retriever(
    search_type="mmr",
    search_kwargs={'k': 6, 'lambda_mult': 0.25}
)

# Fetch more documents for the MMR algorithm to consider
# But only return the top 5
docsearch.as_retriever(
    search_type="mmr",
    search_kwargs={'k': 5, 'fetch_k': 50}
)

# Only retrieve documents that have a relevance score
# Above a certain threshold
docsearch.as_retriever(
    search_type="similarity_score_threshold",
    search_kwargs={'score_threshold': 0.8}
)

# Only get the single most similar document from the dataset
docsearch.as_retriever(search_kwargs={'k': 1})

# Use a filter to only retrieve documents from a specific paper
docsearch.as_retriever(
    search_kwargs={'filter': {'paper_title':'GPT-4 Technical Report'}}
)

async asearch(query: str, search_type: str, **kwargs: Any) → List[Document]¶

Async return docs most similar to query using a specified search type.

Parameters

query (str) – Input text.
search_type (str) – Type of search to perform. Can be “similarity”, “mmr”, or “similarity_score_threshold”.
**kwargs (Any) – Arguments to pass to the search method.

Returns

List of Documents most similar to the query.

Raises

ValueError – If search_type is not one of “similarity”, “mmr”, or “similarity_score_threshold”.

Return type

List[Document]

async asimilarity_search(query: str, k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs most similar to query.

Parameters

query (str) – Text to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
kwargs (Any) –

Returns

List of Document, the most similar to the query vector.

Return type

List[Document]

async asimilarity_search_by_vector(embedding: List[float], k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs most similar to embedding vector.

Parameters

embedding (List[float]) – Embedding to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
kwargs (Any) –

Returns

List of Document, the most similar to the query vector.

Return type

List[Document]

async asimilarity_search_with_relevance_scores(query: str, k: int = 4, **kwargs: Any) → List[Tuple[Document, float]]¶

Async return docs and relevance scores in the range [0, 1].

0 is dissimilar, 1 is most similar.

Parameters

query (str) – Input text.
k (int) – Number of Documents to return. Defaults to 4.
**kwargs (Any) –
kwargs to be passed to similarity search. Should include: score_threshold: Optional, a floating point value between 0 to 1 to

filter the resulting set of retrieved docs

Returns

List of Tuples of (doc, similarity_score)

Return type

List[Tuple[Document, float]]

async asimilarity_search_with_score(query: str, k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float]][source]¶

Return docs most similar to query.

Parameters

query (str) – Text to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score), the most similar to the query vector.

Return type

List[Tuple[Document, float]]

async asimilarity_search_with_score_by_vector(embedding: List[float], k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float]][source]¶

Return docs most similar to embedding vector.

Parameters

embedding (List[float]) – Embedding to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score), the most similar to the query vector.

Return type

List[Tuple[Document, float]]

async asimilarity_search_with_score_id(query: str, k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float, str]][source]¶

Return docs most similar to query.

Parameters

query (str) – Text to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score, id), the most similar to the query vector.

Return type

List[Tuple[Document, float, str]]

async asimilarity_search_with_score_id_by_vector(embedding: List[float], k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float, str]][source]¶

Return docs most similar to embedding vector.

Parameters

embedding (List[float]) – Embedding to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score, id), the most similar to the query vector.

Return type

List[Tuple[Document, float, str]]

astreaming_upsert(items: AsyncIterable[Document], /, batch_size: int, **kwargs: Any) → AsyncIterator[UpsertResponse]¶

[Beta] Upsert documents in a streaming fashion. Async version of streaming_upsert.

Parameters

items (AsyncIterable[Document]) – Iterable of Documents to add to the vectorstore.
batch_size (int) – The size of each batch to upsert.
**kwargs (Any) – Additional keyword arguments. kwargs should only include parameters that are common to all documents. (e.g., timeout for indexing, retry policy, etc.) kwargs should not include ids to avoid ambiguous semantics. Instead the ID should be provided as part of the Document object.

Yields

UpsertResponse – A response object that contains the list of IDs that were successfully added or updated in the vectorstore and the list of IDs that failed to be added or updated.

Return type

AsyncIterator[UpsertResponse]

New in version 0.2.11.

Notes

async aupsert(items: Sequence[Document], /, **kwargs: Any) → UpsertResponse¶

[Beta] Add or update documents in the vectorstore. Async version of upsert.

The upsert functionality should utilize the ID field of the Document object if it is provided. If the ID is not provided, the upsert method is free to generate an ID for the document.

When an ID is specified and the document already exists in the vectorstore, the upsert method should update the document with the new data. If the document does not exist, the upsert method should add the document to the vectorstore.

Parameters

items (Sequence[Document]) – Sequence of Documents to add to the vectorstore.
**kwargs (Any) – Additional keyword arguments.

Returns

A response object that contains the list of IDs that were successfully added or updated in the vectorstore and the list of IDs that failed to be added or updated.

Return type

UpsertResponse

New in version 0.2.11.

Notes

clear() → None[source]¶

Empty the table.

Return type: None

delete(ids: Optional[List[str]] = None, **kwargs: Any) → Optional[bool][source]¶

Delete by vector IDs.

Parameters

ids (Optional[List[str]]) – List of ids to delete.
kwargs (Any) –

Returns

True if deletion is successful, False otherwise, None if not implemented.

Return type

Optional[bool]

delete_by_document_id(document_id: str) → None[source]¶

Delete by document ID.

Parameters: document_id (str) – the document ID to delete.
Return type: None

delete_collection() → None[source]¶

Just an alias for clear (to better align with other VectorStore implementations).

Return type: None

classmethod from_documents(documents: List[Document], embedding: Embeddings, *, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = '', ids: Optional[List[str]] = None, batch_size: int = 16, ttl_seconds: Optional[int] = None, body_index_options: Optional[List[Tuple[str, Any]]] = None, metadata_indexing: Union[Tuple[str, Iterable[str]], str] = 'all', **kwargs: Any) → CVST[source]¶

Create a Cassandra vectorstore from a document list.

Parameters

documents (List[Document]) – Documents to add to the vectorstore.
embedding (Embeddings) – Embedding function to use.
session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.
keyspace (Optional[str]) – Cassandra key space. If not provided, it is resolved from cassio.
table_name (str) – Cassandra table (required).
ids (Optional[List[str]]) – Optional list of IDs associated with the documents.
batch_size (int) – Number of concurrent requests to send to the server. Defaults to 16.
ttl_seconds (Optional[int]) – Optional time-to-live for the added documents.
body_index_options (Optional[List[Tuple[str, Any]]]) – Optional options used to create the body index. Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
metadata_indexing (Union[Tuple[str, Iterable[str]], str]) –
kwargs (Any) –

Returns

a Cassandra vectorstore.

Return type

CVST

classmethod from_texts(texts: List[str], embedding: Embeddings, metadatas: Optional[List[dict]] = None, *, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = '', ids: Optional[List[str]] = None, batch_size: int = 16, ttl_seconds: Optional[int] = None, body_index_options: Optional[List[Tuple[str, Any]]] = None, metadata_indexing: Union[Tuple[str, Iterable[str]], str] = 'all', **kwargs: Any) → CVST[source]¶

Create a Cassandra vectorstore from raw texts.

Parameters

texts (List[str]) – Texts to add to the vectorstore.
embedding (Embeddings) – Embedding function to use.
metadatas (Optional[List[dict]]) – Optional list of metadatas associated with the texts.
session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.
keyspace (Optional[str]) – Cassandra key space. If not provided, it is resolved from cassio.
table_name (str) – Cassandra table (required).
ids (Optional[List[str]]) – Optional list of IDs associated with the texts.
batch_size (int) – Number of concurrent requests to send to the server. Defaults to 16.
ttl_seconds (Optional[int]) – Optional time-to-live for the added texts.
body_index_options (Optional[List[Tuple[str, Any]]]) – Optional options used to create the body index. Eg. body_index_options = [cassio.table.cql.STANDARD_ANALYZER]
metadata_indexing (Union[Tuple[str, Iterable[str]], str]) –
kwargs (Any) –

Returns

a Cassandra vectorstore.

Return type

CVST

get_by_ids(ids: Sequence[str], /) → List[Document]¶

Get documents by their IDs.

The returned documents are expected to have the ID field set to the ID of the document in the vector store.

Fewer documents may be returned than requested if some IDs are not found or if there are duplicated IDs.

Users should not assume that the order of the returned documents matches the order of the input IDs. Instead, users should rely on the ID field of the returned documents.

This method should NOT raise exceptions if no documents are found for some IDs.

Parameters: ids (Sequence[str]) – List of ids to retrieve.
Returns: List of Documents.
Return type: List[Document]

New in version 0.2.11.

max_marginal_relevance_search(query: str, k: int = 4, fetch_k: int = 20, lambda_mult: float = 0.5, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param query: Text to look up documents similar to. :param k: Number of Documents to return. Defaults to 4. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm.

Defaults to 20.

Parameters

lambda_mult (float) – Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
query (str) –
k (int) –
fetch_k (int) –
kwargs (Any) –

Returns

List of Documents selected by maximal marginal relevance.

Return type

List[Document]

max_marginal_relevance_search_by_vector(embedding: List[float], k: int = 4, fetch_k: int = 20, lambda_mult: float = 0.5, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs selected using the maximal marginal relevance. Maximal marginal relevance optimizes for similarity to query AND diversity among selected documents. :param embedding: Embedding to look up documents similar to. :param k: Number of Documents to return. Defaults to 4. :param fetch_k: Number of Documents to fetch to pass to MMR algorithm.

Defaults to 20.

Parameters

lambda_mult (float) – Number between 0 and 1 that determines the degree of diversity among the results with 0 corresponding to maximum diversity and 1 to minimum diversity. Defaults to 0.5.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
embedding (List[float]) –
k (int) –
fetch_k (int) –
kwargs (Any) –

Returns

List of Documents selected by maximal marginal relevance.

Return type

List[Document]

search(query: str, search_type: str, **kwargs: Any) → List[Document]¶

Return docs most similar to query using a specified search type.

Parameters

query (str) – Input text
search_type (str) – Type of search to perform. Can be “similarity”, “mmr”, or “similarity_score_threshold”.
**kwargs (Any) – Arguments to pass to the search method.

Returns

List of Documents most similar to the query.

Raises

ValueError – If search_type is not one of “similarity”, “mmr”, or “similarity_score_threshold”.

Return type

List[Document]

similarity_search(query: str, k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs most similar to query.

Parameters

query (str) – Text to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
kwargs (Any) –

Returns

List of Document, the most similar to the query vector.

Return type

List[Document]

similarity_search_by_vector(embedding: List[float], k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None, **kwargs: Any) → List[Document][source]¶

Return docs most similar to embedding vector.

Parameters

embedding (List[float]) – Embedding to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.
kwargs (Any) –

Returns

List of Document, the most similar to the query vector.

Return type

List[Document]

similarity_search_with_relevance_scores(query: str, k: int = 4, **kwargs: Any) → List[Tuple[Document, float]]¶

Return docs and relevance scores in the range [0, 1].

0 is dissimilar, 1 is most similar.

Parameters

query (str) – Input text.
k (int) – Number of Documents to return. Defaults to 4.
**kwargs (Any) –
kwargs to be passed to similarity search. Should include: score_threshold: Optional, a floating point value between 0 to 1 to

filter the resulting set of retrieved docs.

Returns

List of Tuples of (doc, similarity_score).

Return type

List[Tuple[Document, float]]

similarity_search_with_score(query: str, k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float]][source]¶

Return docs most similar to query.

Parameters

query (str) – Text to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score), the most similar to the query vector.

Return type

List[Tuple[Document, float]]

similarity_search_with_score_by_vector(embedding: List[float], k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float]][source]¶

Return docs most similar to embedding vector.

Parameters

embedding (List[float]) – Embedding to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score), the most similar to the query vector.

Return type

List[Tuple[Document, float]]

similarity_search_with_score_id(query: str, k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float, str]][source]¶

Return docs most similar to query.

Parameters

query (str) – Text to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score, id), the most similar to the query vector.

Return type

List[Tuple[Document, float, str]]

similarity_search_with_score_id_by_vector(embedding: List[float], k: int = 4, filter: Optional[Dict[str, str]] = None, body_search: Optional[Union[str, List[str]]] = None) → List[Tuple[Document, float, str]][source]¶

Return docs most similar to embedding vector.

Parameters

embedding (List[float]) – Embedding to look up documents similar to.
k (int) – Number of Documents to return. Defaults to 4.
filter (Optional[Dict[str, str]]) – Filter on the metadata to apply.
body_search (Optional[Union[str, List[str]]]) – Document textual search terms to apply. Only supported by Astra DB at the moment.

Returns

List of (Document, score, id), the most similar to the query vector.

Return type

List[Tuple[Document, float, str]]

streaming_upsert(items: Iterable[Document], /, batch_size: int, **kwargs: Any) → Iterator[UpsertResponse]¶

[Beta] Upsert documents in a streaming fashion.

Parameters

items (Iterable[Document]) – Iterable of Documents to add to the vectorstore.
batch_size (int) – The size of each batch to upsert.
**kwargs (Any) – Additional keyword arguments. kwargs should only include parameters that are common to all documents. (e.g., timeout for indexing, retry policy, etc.) kwargs should not include ids to avoid ambiguous semantics. Instead, the ID should be provided as part of the Document object.

Yields

UpsertResponse – A response object that contains the list of IDs that were successfully added or updated in the vectorstore and the list of IDs that failed to be added or updated.

Return type

Iterator[UpsertResponse]

New in version 0.2.11.

Notes

upsert(items: Sequence[Document], /, **kwargs: Any) → UpsertResponse¶

[Beta] Add or update documents in the vectorstore.

The upsert functionality should utilize the ID field of the Document object if it is provided. If the ID is not provided, the upsert method is free to generate an ID for the document.

When an ID is specified and the document already exists in the vectorstore, the upsert method should update the document with the new data. If the document does not exist, the upsert method should add the document to the vectorstore.

Parameters

items (Sequence[Document]) – Sequence of Documents to add to the vectorstore.
**kwargs (Any) – Additional keyword arguments.

Returns

A response object that contains the list of IDs that were successfully added or updated in the vectorstore and the list of IDs that failed to be added or updated.

Return type

UpsertResponse

New in version 0.2.11.

Notes

langchain_community.vectorstores.cassandra.Cassandra¶

Examples using Cassandra¶

`langchain_community.vectorstores.cassandra`.Cassandra¶