Source code for getml.sqlite3.read_pandas

# Copyright 2022 The SQLNet Company GmbH
# This file is licensed under the Elastic License 2.0 (ELv2).
# Refer to the LICENSE.txt file in the root of the repository
# for details.

Contains utility functions for reading a pandas DataFrame
into sqlite3.

import numbers
import sqlite3

import pandas as pd  # type: ignore

from .helpers import _create_table, _get_colnames, _log
from .read_list import read_list
from .sniff_pandas import sniff_pandas

[docs]def read_pandas(conn, table_name, data_frame, if_exists="append"): """ Loads a pandas.DataFrame into SQLite3. Args: conn: A sqlite3 connection created by :func:`~getml.sqlite3.connect`. table_name (str): The name of the table to write to. data_frame (pandas.DataFrame): The pandas.DataFrame to read into the table. The column names must match the column names of the target table in the SQLite3 database, but their order is not important. if_exists (str): How to behave if the table already exists: - 'fail': Raise a ValueError. - 'replace': Drop the table before inserting new values. - 'append': Insert new values into the existing table. """ # ------------------------------------------------------------ if not isinstance(conn, sqlite3.Connection): raise TypeError("'conn' must be an sqlite3.Connection object") if not isinstance(table_name, str): raise TypeError("'table_name' must be a str") if not isinstance(data_frame, pd.DataFrame): raise TypeError("'data_frame' must be a pandas.DataFrame") if not isinstance(if_exists, str): raise TypeError("'if_exists' must be a str") # ------------------------------------------------------------ _log("Loading pandas.DataFrame into '" + table_name + "'...") schema = sniff_pandas(table_name, data_frame) _create_table(conn, table_name, schema, if_exists) colnames = _get_colnames(conn, table_name) data = data_frame[colnames].values.tolist() data = [ [ field if isinstance(field, (numbers.Number, str)) or field is None else str(field) for field in row ] for row in data ] read_list(conn, table_name, data)