types.SQLAlchemySource

SQLAlchemySource(engine, table_name)

A DataSource implementation that supports multiple SQL databases via SQLAlchemy.

Supports various databases including PostgreSQL, MySQL, SQLite, Snowflake, and Databricks.

Methods

Name	Description
cleanup	Dispose of the SQLAlchemy engine.
execute_query	Execute SQL query and return results as DataFrame.
get_data	Return the unfiltered data as a DataFrame.
get_db_type	Get the database type.
get_schema	Generate schema information from database table.
get_semantic_views_description	Get information about semantic views (if any) for the system prompt.
test_query	Test query by fetching only one row.

cleanup

types.SQLAlchemySource.cleanup()

Dispose of the SQLAlchemy engine.

Returns

Name	Type	Description
	None

execute_query

types.SQLAlchemySource.execute_query(query)

Execute SQL query and return results as DataFrame.

Parameters

Name	Type	Description	Default
query	str	SQL query to execute	required

Returns

Name	Type	Description
	nw.DataFrame	Query results as narwhals DataFrame

Raises

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

get_data

types.SQLAlchemySource.get_data()

Return the unfiltered data as a DataFrame.

Returns

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

get_db_type

types.SQLAlchemySource.get_db_type()

Get the database type.

Returns the specific database type (e.g., POSTGRESQL, MYSQL, SQLITE) by inspecting the SQLAlchemy engine. Removes ” SQL” suffix if present.

get_schema

types.SQLAlchemySource.get_schema(categorical_threshold)

Generate schema information from database table.

Parameters

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

Returns

Name	Type	Description
	str	String describing the schema

get_semantic_views_description

types.SQLAlchemySource.get_semantic_views_description()

Get information about semantic views (if any) for the system prompt.

test_query

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

Test query by fetching only one row.

Parameters

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

Returns

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

Raises

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