Class PostgresLoader (0.5.0)

PostgresLoader(
    key,
    engine: langchain_google_cloud_sql_pg.engine.PostgresEngine,
    query: str,
    content_columns: typing.List[str],
    metadata_columns: typing.List[str],
    formatter: typing.Callable,
    metadata_json_column: typing.Optional[str] = None,
)

Load documents from PostgreSQL`.

Each document represents one row of the result. The content_columns are written into the content_columnsof the document. The metadata_columns are written into the metadata_columns of the document. By default, first columns is written into the page_content and everything else into the metadata.

Methods

alazy_load

alazy_load() -> typing.AsyncIterator[langchain_core.documents.base.Document]

Load PostgreSQL data into Document objects lazily.

aload

aload() -> typing.List[langchain_core.documents.base.Document]

Load PostgreSQL data into Document objects.

create

create(
    engine: langchain_google_cloud_sql_pg.engine.PostgresEngine,
    query: typing.Optional[str] = None,
    table_name: typing.Optional[str] = None,
    content_columns: typing.Optional[typing.List[str]] = None,
    metadata_columns: typing.Optional[typing.List[str]] = None,
    metadata_json_column: typing.Optional[str] = None,
    format: typing.Optional[str] = None,
    formatter: typing.Optional[typing.Callable] = None,
)

Constructor for PostgresLoader

Parameters
Name	Description
`engine`	`PostgresEngine` AsyncEngine with pool connection to the postgres database
`query`	`Optional[str], optional` SQL query. Defaults to None.
`table_name`	`Optional[str], optional` Name of table to query. Defaults to None.
`content_columns`	`Optional[List[str]], optional` Column that represent a Document's page_content. Defaults to the first column.
`metadata_columns`	`Optional[List[str]], optional` Column(s) that represent a Document's metadata.. Defaults to None.
`metadata_json_column`	`Optional[str], optional` Column to store metadata as JSON. Defaults to "langchain_metadata".
`format`	`Optional[str], optional` Format of page content (OneOf: text, csv, YAML, JSON). Defaults to 'text'.
`formatter`	`Optional[Callable], optional` A function to format page content (OneOf: format, formatter). Defaults to None.

lazy_load

lazy_load() -> typing.Iterator[langchain_core.documents.base.Document]