From 1ef5a875dbf51401b41853a8688835c551fccba9 Mon Sep 17 00:00:00 2001 From: Guilherme Martins Crocetti <24530683+gmcrocetti@users.noreply.github.com> Date: Fri, 2 Aug 2024 15:40:37 -0300 Subject: [PATCH] feat: implement option 'delete_rows' of argument 'if_exists' in 'DataFrame.to_sql' API. --- doc/source/whatsnew/v3.0.0.rst | 1 + pandas/io/sql.py | 56 ++++++++++++++++++++++++------ pandas/tests/io/test_sql.py | 62 +++++++++++++++++++++++++++++++++- 3 files changed, 107 insertions(+), 12 deletions(-) diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst index 120ee978292d6..9c500654e9942 100644 --- a/doc/source/whatsnew/v3.0.0.rst +++ b/doc/source/whatsnew/v3.0.0.rst @@ -59,6 +59,7 @@ Other enhancements - :meth:`Series.map` can now accept kwargs to pass on to func (:issue:`59814`) - :meth:`pandas.concat` will raise a ``ValueError`` when ``ignore_index=True`` and ``keys`` is not ``None`` (:issue:`59274`) - :meth:`str.get_dummies` now accepts a ``dtype`` parameter to specify the dtype of the resulting DataFrame (:issue:`47872`) +- Add ``"delete_rows"`` option to ``if_exists`` argument in :meth:`DataFrame.to_sql` deleting all records of the table before inserting data (:issue:`37210`). - Multiplying two :class:`DateOffset` objects will now raise a ``TypeError`` instead of a ``RecursionError`` (:issue:`59442`) - Restore support for reading Stata 104-format and enable reading 103-format dta files (:issue:`58554`) - Support passing a :class:`Iterable[Hashable]` input to :meth:`DataFrame.drop_duplicates` (:issue:`59237`) diff --git a/pandas/io/sql.py b/pandas/io/sql.py index 3c0c5cc64c24c..c885f1c767d96 100644 --- a/pandas/io/sql.py +++ b/pandas/io/sql.py @@ -738,7 +738,7 @@ def to_sql( name: str, con, schema: str | None = None, - if_exists: Literal["fail", "replace", "append"] = "fail", + if_exists: Literal["fail", "replace", "append", "delete_rows"] = "fail", index: bool = True, index_label: IndexLabel | None = None, chunksize: int | None = None, @@ -764,10 +764,11 @@ def to_sql( schema : str, optional Name of SQL schema in database to write to (if database flavor supports this). If None, use default schema (default). - if_exists : {'fail', 'replace', 'append'}, default 'fail' + if_exists : {'fail', 'replace', 'append', 'delete_rows'}, default 'fail' - fail: If table exists, do nothing. - replace: If table exists, drop it, recreate it, and insert data. - append: If table exists, insert data. Create if does not exist. + - delete_rows: If a table exists, delete all records and insert data. index : bool, default True Write DataFrame index as a column. index_label : str or sequence, optional @@ -818,7 +819,7 @@ def to_sql( `sqlite3 `__ or `SQLAlchemy `__ """ # noqa: E501 - if if_exists not in ("fail", "replace", "append"): + if if_exists not in ("fail", "replace", "append", "delete_rows"): raise ValueError(f"'{if_exists}' is not valid for if_exists") if isinstance(frame, Series): @@ -926,7 +927,7 @@ def __init__( pandas_sql_engine, frame=None, index: bool | str | list[str] | None = True, - if_exists: Literal["fail", "replace", "append"] = "fail", + if_exists: Literal["fail", "replace", "append", "delete_rows"] = "fail", prefix: str = "pandas", index_label=None, schema=None, @@ -974,11 +975,13 @@ def create(self) -> None: if self.exists(): if self.if_exists == "fail": raise ValueError(f"Table '{self.name}' already exists.") - if self.if_exists == "replace": + elif self.if_exists == "replace": self.pd_sql.drop_table(self.name, self.schema) self._execute_create() elif self.if_exists == "append": pass + elif self.if_exists == "delete_rows": + self.pd_sql.delete_rows(self.name, self.schema) else: raise ValueError(f"'{self.if_exists}' is not valid for if_exists") else: @@ -1480,7 +1483,7 @@ def to_sql( self, frame, name: str, - if_exists: Literal["fail", "replace", "append"] = "fail", + if_exists: Literal["fail", "replace", "append", "delete_rows"] = "fail", index: bool = True, index_label=None, schema=None, @@ -1866,7 +1869,7 @@ def prep_table( self, frame, name: str, - if_exists: Literal["fail", "replace", "append"] = "fail", + if_exists: Literal["fail", "replace", "append", "delete_rows"] = "fail", index: bool | str | list[str] | None = True, index_label=None, schema=None, @@ -1943,7 +1946,7 @@ def to_sql( self, frame, name: str, - if_exists: Literal["fail", "replace", "append"] = "fail", + if_exists: Literal["fail", "replace", "append", "delete_rows"] = "fail", index: bool = True, index_label=None, schema: str | None = None, @@ -1961,10 +1964,11 @@ def to_sql( frame : DataFrame name : string Name of SQL table. - if_exists : {'fail', 'replace', 'append'}, default 'fail' + if_exists : {'fail', 'replace', 'append', 'delete_rows'}, default 'fail' - fail: If table exists, do nothing. - replace: If table exists, drop it, recreate it, and insert data. - append: If table exists, insert data. Create if does not exist. + - delete_rows: If a table exists, delete all records and insert data. index : boolean, default True Write DataFrame index as a column. index_label : string or sequence, default None @@ -2061,6 +2065,18 @@ def drop_table(self, table_name: str, schema: str | None = None) -> None: self.get_table(table_name, schema).drop(bind=self.con) self.meta.clear() + def delete_rows(self, table_name: str, schema: str | None = None) -> None: + schema = schema or self.meta.schema + if self.has_table(table_name, schema): + self.meta.reflect( + bind=self.con, only=[table_name], schema=schema, views=True + ) + with self.run_transaction() as con: + table = self.get_table(table_name, schema) + con.execute(table.delete()) + + self.meta.clear() + def _create_sql_schema( self, frame: DataFrame, @@ -2296,7 +2312,7 @@ def to_sql( self, frame, name: str, - if_exists: Literal["fail", "replace", "append"] = "fail", + if_exists: Literal["fail", "replace", "append", "delete_rows"] = "fail", index: bool = True, index_label=None, schema: str | None = None, @@ -2318,6 +2334,7 @@ def to_sql( - fail: If table exists, do nothing. - replace: If table exists, drop it, recreate it, and insert data. - append: If table exists, insert data. Create if does not exist. + - delete_rows: If a table exists, delete all records and insert data. index : boolean, default True Write DataFrame index as a column. index_label : string or sequence, default None @@ -2335,6 +2352,7 @@ def to_sql( engine : {'auto', 'sqlalchemy'}, default 'auto' Raises NotImplementedError if not set to 'auto' """ + if index_label: raise NotImplementedError( "'index_label' is not implemented for ADBC drivers" @@ -2368,6 +2386,9 @@ def to_sql( cur.execute(f"DROP TABLE {table_name}") elif if_exists == "append": mode = "append" + elif if_exists == "delete_rows": + mode = "append" + self.delete_rows(name, schema) import pyarrow as pa @@ -2402,6 +2423,12 @@ def has_table(self, name: str, schema: str | None = None) -> bool: return False + def delete_rows(self, name: str, schema: str | None = None) -> None: + delete_sql = f"DELETE FROM {schema}.{name}" if schema else f"DELETE FROM {name}" + if self.has_table(name, schema): + with self.con.cursor() as cur: + cur.execute(delete_sql) + def _create_sql_schema( self, frame: DataFrame, @@ -2769,10 +2796,11 @@ def to_sql( frame: DataFrame name: string Name of SQL table. - if_exists: {'fail', 'replace', 'append'}, default 'fail' + if_exists: {'fail', 'replace', 'append', 'delete_rows'}, default 'fail' fail: If table exists, do nothing. replace: If table exists, drop it, recreate it, and insert data. append: If table exists, insert data. Create if it does not exist. + delete_rows: If a table exists, delete all records and insert data. index : bool, default True Write DataFrame index as a column index_label : string or sequence, default None @@ -2848,6 +2876,12 @@ def drop_table(self, name: str, schema: str | None = None) -> None: drop_sql = f"DROP TABLE {_get_valid_sqlite_name(name)}" self.execute(drop_sql) + def delete_rows(self, name: str, schema: str | None = None) -> None: + delete_sql = f"DELETE FROM {_get_valid_sqlite_name(name)}" + if self.has_table(name, schema): + with self.run_transaction() as cur: + cur.execute(delete_sql) + def _create_sql_schema( self, frame, diff --git a/pandas/tests/io/test_sql.py b/pandas/tests/io/test_sql.py index 7e1220ecee218..06a1110c76d4c 100644 --- a/pandas/tests/io/test_sql.py +++ b/pandas/tests/io/test_sql.py @@ -1068,7 +1068,9 @@ def test_to_sql(conn, method, test_frame1, request): @pytest.mark.parametrize("conn", all_connectable) -@pytest.mark.parametrize("mode, num_row_coef", [("replace", 1), ("append", 2)]) +@pytest.mark.parametrize( + "mode, num_row_coef", [("replace", 1), ("append", 2), ("delete_rows", 1)] +) def test_to_sql_exist(conn, mode, num_row_coef, test_frame1, request): conn = request.getfixturevalue(conn) with pandasSQL_builder(conn, need_transaction=True) as pandasSQL: @@ -2698,6 +2700,64 @@ def test_drop_table(conn, request): assert not insp.has_table("temp_frame") +@pytest.mark.parametrize("conn", all_connectable) +def test_delete_rows_success(conn, test_frame1, request): + table_name = "temp_frame" + conn = request.getfixturevalue(conn) + pandasSQL = pandasSQL_builder(conn) + + with pandasSQL.run_transaction(): + assert pandasSQL.to_sql(test_frame1, table_name) == test_frame1.shape[0] + + with pandasSQL.run_transaction(): + assert pandasSQL.delete_rows(table_name) is None + + assert count_rows(conn, table_name) == 0 + assert pandasSQL.has_table("temp_frame") + + +@pytest.mark.parametrize("conn", all_connectable) +def test_delete_rows_is_atomic(conn, request): + import adbc_driver_manager + import sqlalchemy + + if "sqlite" in conn: + reason = "This test relies on strict column types, SQLite has a dynamic one" + request.applymarker( + pytest.mark.xfail( + reason=reason, + strict=True, + ) + ) + + table_name = "temp_frame" + original_df = DataFrame({"a": [1, 2, 3]}) + replacing_df = DataFrame({"a": ["a", "b", "c", "d"]}) + + conn = request.getfixturevalue(conn) + pandasSQL = pandasSQL_builder(conn) + + if isinstance(conn, adbc_driver_manager.dbapi.Connection): + expected_exception = adbc_driver_manager.ProgrammingError + else: + expected_exception = sqlalchemy.exc.DataError + + class Foo(Exception): ... + + with pandasSQL.run_transaction(): + pandasSQL.to_sql(original_df, table_name, if_exists="fail", index=False) + + with pytest.raises(expected_exception): + with pandasSQL.run_transaction(): + pandasSQL.to_sql( + replacing_df, table_name, if_exists="delete_rows", index=False + ) + + with pandasSQL.run_transaction(): + result_df = pandasSQL.read_query(f"SELECT * FROM {table_name}") + tm.assert_frame_equal(result_df, original_df) + + @pytest.mark.parametrize("conn", all_connectable) def test_roundtrip(conn, request, test_frame1): if conn == "sqlite_str":