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TYP: add return types to read_sql|read_sql_query|read_sql_table #34207

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Merged
merged 3 commits into from
May 21, 2020
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TYP: add return types to read_sql|read_sql_query|read_sql_table #34207

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8b3e988
TYP: add return types to read_sql|read_sql_query|read_sql_table
topper-123 May 16, 2020
16d478d
clean according to comments
topper-123 May 19, 2020
c2c7107
switch return types
topper-123 May 21, 2020
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103 changes: 93 additions & 10 deletions pandas/io/sql.py
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
from datetime import date, datetime, time
from functools import partial
import re
from typing import Iterator, Optional, Union, overload
import warnings

import numpy as np
Expand Down Expand Up @@ -162,6 +163,7 @@ def execute(sql, con, cur=None, params=None):
# -- Read and write to DataFrames


@overload
def read_sql_table(
table_name,
con,
Expand All @@ -170,8 +172,35 @@ def read_sql_table(
coerce_float=True,
parse_dates=None,
columns=None,
chunksize=None,
):
chunksize: None = None,
) -> DataFrame:
...


@overload
def read_sql_table(
table_name,
con,
schema=None,
index_col=None,
coerce_float=True,
parse_dates=None,
columns=None,
chunksize: int = 1,
) -> Iterator[DataFrame]:
...


def read_sql_table(
table_name,
con,
schema=None,
index_col=None,
coerce_float=True,
parse_dates=None,
columns=None,
chunksize: Optional[int] = None,
) -> Union[DataFrame, Iterator[DataFrame]]:
"""
Read SQL database table into a DataFrame.

Expand Down Expand Up @@ -210,7 +239,7 @@ def read_sql_table(

Returns
-------
DataFrame
DataFrame or Iterator[DataFrame]
A SQL table is returned as two-dimensional data structure with labeled
axes.

Expand Down Expand Up @@ -257,15 +286,41 @@ def read_sql_table(
raise ValueError(f"Table {table_name} not found", con)


@overload
def read_sql_query(
sql,
con,
index_col=None,
coerce_float=True,
params=None,
parse_dates=None,
chunksize=None,
):
chunksize: None = None,
) -> DataFrame:
...


@overload
def read_sql_query(
sql,
con,
index_col=None,
coerce_float=True,
params=None,
parse_dates=None,
chunksize: int = 1,
) -> Iterator[DataFrame]:
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@simonjayhawkins simonjayhawkins May 20, 2020

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are the return types of the two overloads switched? or have a misread the docstring?

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@WillAyd WillAyd May 20, 2020

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Yea looks like a copy / paste error? The other two funcs look correct.

lgtm outside of this issue

...


def read_sql_query(
sql,
con,
index_col=None,
coerce_float=True,
params=None,
parse_dates=None,
chunksize: Optional[int] = None,
) -> Union[DataFrame, Iterator[DataFrame]]:
"""
Read SQL query into a DataFrame.

Expand Down Expand Up @@ -308,7 +363,7 @@ def read_sql_query(

Returns
-------
DataFrame
DataFrame or Iterator[DataFrame]

See Also
--------
Expand All @@ -331,6 +386,7 @@ def read_sql_query(
)


@overload
def read_sql(
sql,
con,
Expand All @@ -339,8 +395,35 @@ def read_sql(
params=None,
parse_dates=None,
columns=None,
chunksize=None,
):
chunksize: None = None,
) -> DataFrame:
...


@overload
def read_sql(
sql,
con,
index_col=None,
coerce_float=True,
params=None,
parse_dates=None,
columns=None,
chunksize: int = 1,
) -> Iterator[DataFrame]:
...


def read_sql(
sql,
con,
index_col=None,
coerce_float=True,
params=None,
parse_dates=None,
columns=None,
chunksize: Optional[int] = None,
) -> Union[DataFrame, Iterator[DataFrame]]:
"""
Read SQL query or database table into a DataFrame.

Expand Down Expand Up @@ -391,7 +474,7 @@ def read_sql(

Returns
-------
DataFrame
DataFrame or Iterator[DataFrame]

See Also
--------
Expand Down Expand Up @@ -448,7 +531,7 @@ def to_sql(
chunksize=None,
dtype=None,
method=None,
):
) -> None:
"""
Write records stored in a DataFrame to a SQL database.

Expand Down