types.DataFrameSource

DataFrameSource(df, table_name)

A DataSource implementation that wraps a DataFrame using DuckDB.

Methods

Name	Description
cleanup	Close the DuckDB connection.
execute_query	Execute query using DuckDB.
get_data	Return the unfiltered data as a DataFrame.
get_db_type	Get the database type.
get_schema	Generate schema information from DataFrame.
test_query	Test query by fetching only one row.

types.DataFrameSource.cleanup()

Close the DuckDB connection.

Name	Type	Description
	None

types.DataFrameSource.execute_query(query)

Execute query using DuckDB.

Uses polars if available, otherwise falls back to pandas.

Name	Type	Description	Default
query	str	SQL query to execute	required

Name	Type	Description
	`nw`.`DataFrame`	Query results as narwhals DataFrame

Name	Type	Description
	`UnsafeQueryError`	If the query starts with a disallowed SQL operation

types.DataFrameSource.get_data()

Return the unfiltered data as a DataFrame.

Name	Type	Description
	`nw`.`DataFrame`	The complete dataset as a narwhals DataFrame

types.DataFrameSource.get_db_type()

Get the database type.

Name	Type	Description
	str	The string “DuckDB”

types.DataFrameSource.get_schema(categorical_threshold)

Generate schema information from DataFrame.

Name	Type	Description	Default
categorical_threshold	int	Maximum number of unique values for a text column to be considered categorical	required

Name	Type	Description
	str	String describing the schema

types.DataFrameSource.test_query(query, *, require_all_columns=False)

Test query by fetching only one row.

Name	Type	Description	Default
query	str	SQL query to test	required
require_all_columns	bool	If True, validates that result includes all original table columns	`False`

Name	Type	Description
	`nw`.`DataFrame`	Query results with at most one row

Name	Type	Description
	`UnsafeQueryError`	If the query starts with a disallowed SQL operation
	`MissingColumnsError`	If require_all_columns is True and result is missing required columns