Return VectorStore initialized from documents and embeddings.
        Postgres connection string is required
        "Either pass it as a parameter
        or set the HOLOGRES_CONNECTION_STRING environment variable.
        Example:
            .. code-block:: python
                from langchain import Hologres
                from langchain.embeddings import OpenAIEmbeddings
                embeddings = OpenAIEmbeddings()
                text_embeddings = embeddings.embed_documents(texts)
                text_embedding_pairs = list(zip(texts, text_embeddings))
                faiss = Hologres.from_embeddings(text_embedding_pairs, embeddings)
        """
        texts = [t[0] for t in text_embeddings]
        embeddings = [t[1] for t in text_embeddings]
        return cls.__from(
            texts,
            embeddings,
            embedding,
            metadatas=metadatas,
            ids=ids,
            ndims=ndims,
            table_name=table_name,
            pre_delete_table=pre_delete_table,
            **kwargs,
        )
[docs]    @classmethod
    def from_existing_index(
        cls: Type[Hologres],
        embedding: Embeddings,
        ndims: int = ADA_TOKEN_COUNT,
        table_name: str = _LANGCHAIN_DEFAULT_TABLE_NAME,
        pre_delete_table: bool = False,
        **kwargs: Any,
    ) -> Hologres:
        """
        Get intsance of an existing Hologres store.This method will
        return the instance of the store without inserting any new
        embeddings
        """
        connection_string = cls.get_connection_string(kwargs)
        store = cls(
            connection_string=connection_string,
            ndims=ndims,
            table_name=table_name,
            embedding_function=embedding,
            pre_delete_table=pre_delete_table,
rtdocs_stable/api.python.langchain.com/en/stable/_modules/langchain/vectorstores/hologres.html