Source code for langchain_community.document_loaders.duckdb_loader

from typing import Dict, List, Optional, cast

from langchain_core.documents import Document

from langchain_community.document_loaders.base import BaseLoader

[docs]class DuckDBLoader(BaseLoader): """Load from `DuckDB`. Each document represents one row of the result. The `page_content_columns` are written into the `page_content` of the document. The `metadata_columns` are written into the `metadata` of the document. By default, all columns are written into the `page_content` and none into the `metadata`. """
[docs] def __init__( self, query: str, database: str = ":memory:", read_only: bool = False, config: Optional[Dict[str, str]] = None, page_content_columns: Optional[List[str]] = None, metadata_columns: Optional[List[str]] = None, ): """ Args: query: The query to execute. database: The database to connect to. Defaults to ":memory:". read_only: Whether to open the database in read-only mode. Defaults to False. config: A dictionary of configuration options to pass to the database. Optional. page_content_columns: The columns to write into the `page_content` of the document. Optional. metadata_columns: The columns to write into the `metadata` of the document. Optional. """ self.query = query self.database = database self.read_only = read_only self.config = config or {} self.page_content_columns = page_content_columns self.metadata_columns = metadata_columns
[docs] def load(self) -> List[Document]: try: import duckdb except ImportError: raise ImportError( "Could not import duckdb python package. " "Please install it with `pip install duckdb`." ) docs = [] with duckdb.connect( database=self.database, read_only=self.read_only, config=self.config ) as con: query_result = con.execute(self.query) results = query_result.fetchall() description = cast(list, query_result.description) field_names = [c[0] for c in description] if self.page_content_columns is None: page_content_columns = field_names else: page_content_columns = self.page_content_columns if self.metadata_columns is None: metadata_columns = [] else: metadata_columns = self.metadata_columns for result in results: page_content = "\n".join( f"{column}: {result[field_names.index(column)]}" for column in page_content_columns ) metadata = { column: result[field_names.index(column)] for column in metadata_columns } doc = Document(page_content=page_content, metadata=metadata) docs.append(doc) return docs