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Bigtable is a key-value and wide-column store, ideal for fast access to structured, semi-structured, or unstructured data. Extend your database application to build AI-powered experiences leveraging Bigtable’s LangChain integrations.
This notebook goes over how to use Bigtable to save, load and delete langchain documents with BigtableLoader and BigtableSaver. Learn more about the package on GitHub. Open In Colab

Before you begin

To run this notebook, you will need to do the following: After confirmed access to database in the runtime environment of this notebook, filling the following values and run the cell before running example scripts.

🦜🔗 Library installation

The integration lives in its own langchain-google-bigtable package, so we need to install it.
Colab only: Uncomment the following cell to restart the kernel or use the button to restart the kernel. For Vertex AI Workbench you can restart the terminal using the button on top.

Set your Google Cloud project

Set your Google Cloud project so that you can leverage Google Cloud resources within this notebook. If you don’t know your project ID, try the following:

Authentication

Authenticate to Google Cloud as the IAM user logged into this notebook in order to access your Google Cloud Project.

Basic usage

Using the saver

Save langchain documents with BigtableSaver.add_documents(<documents>). To initialize BigtableSaver class you need to provide 2 things:
  1. instance_id - An instance of Bigtable.
  2. table_id - The name of the table within the Bigtable to store langchain documents.

Querying for documents from bigtable

For more details on connecting to a Bigtable table, please check the Python SDK documentation.

Load documents from table

Load langchain documents with BigtableLoader.load() or BigtableLoader.lazy_load(). lazy_load returns a generator that only queries database during the iteration. To initialize BigtableLoader class you need to provide:
  1. instance_id - An instance of Bigtable.
  2. table_id - The name of the table within the Bigtable to store langchain documents.

Delete documents

Delete a list of langchain documents from Bigtable table with BigtableSaver.delete(<documents>).

Advanced usage

Limiting the returned rows

There are two ways to limit the returned rows:
  1. Using a filter
  2. Using a row_set

Custom client

The client created by default is the default client, using only admin=True option. To use a non-default, a custom client can be passed to the constructor.

Custom content

The BigtableLoader assumes there is a column family called langchain, that has a column called content, that contains values encoded in UTF-8. These defaults can be changed like so:

Metadata mapping

By default, the metadata map on the Document object will contain a single key, rowkey, with the value of the row’s rowkey value. To add more items to that map, use metadata_mapping.

Metadata as JSON

If there is a column in Bigtable that contains a JSON string that you would like to have added to the output document metadata, it is possible to add the following parameters to BigtableLoader. Note, the default value for metadata_as_json_encoding is UTF-8.

Customize BigtableSaver

The BigtableSaver is also customizable similar to BigtableLoader.