feat(datasets): make table write mode configurable

kedro-datasets/RELEASE.md

@@ -1,4 +1,5 @@
 # Upcoming Release
+
 ## Major features and improvements
 
 - Group datasets documentation according to the dependencies to clean up the nav bar.
@@ -15,14 +16,20 @@
 | ------------------------------ | ------------------------------------------------------------- | ------------------------------------ |
 | `polars.PolarsDatabaseDataset` | A dataset to load and save data to a SQL backend using Polars | `kedro_datasets_experimental.polars` |
 
+- Added `mode` save argument to `ibis.TableDataset`, supporting "append", "overwrite", "error"/"errorifexists", and "ignore" save modes. The `overwrite` save argument is mapped to `mode` for backward compatibility; specifying both results in an error.
+
 ## Bug fixes and other changes
 
 - Added primary key constraint to BaseTable.
 - Added save/load with `use_pyarrow=True` save_args for LazyPolarsDataset partitioned parquet files.
 - Updated the json schema for Kedro 1.0.0.
 
 ## Breaking Changes
+
+- `ibis.TableDataset`: Deprecated `save_args.overwrite` and the `connection` parameter in favor of `save_args.mode` and `credentials`. Using both `overwrite` and `mode` together raises an error; providing both `credentials` and `connection` emits a deprecation warning. The deprecated options will be removed in a future release.
+
 ## Community contributions
+
 - [Minura Punchihewa](https://github.com/MinuraPunchihewa)
 - [gitgud5000](https://github.com/gitgud5000)
 
@@ -56,7 +63,6 @@ Many thanks to the following Kedroids for contributing PRs to this release:
 - [Seohyun Park](https://github.com/soyamimi)
 - [Daniel Russell-Brain](https://github.com/killerfridge)
 
-
 # Release 7.0.0
 
 ## Major features and improvements

kedro-datasets/kedro_datasets/ibis/table_dataset.py

@@ -1,18 +1,35 @@
 """Provide data loading and saving functionality for Ibis's backends."""
 from __future__ import annotations
 
+import sys
 from copy import deepcopy
+from enum import auto
 from typing import TYPE_CHECKING, Any, ClassVar
 
+if sys.version_info >= (3, 11):
+    from enum import StrEnum  # pragma: no cover
+else:
+    from backports.strenum import StrEnum  # pragma: no cover
+
 import ibis.expr.types as ir
-from kedro.io import AbstractDataset
+from kedro.io import AbstractDataset, DatasetError
 
 from kedro_datasets._utils import ConnectionMixin
 
 if TYPE_CHECKING:
     from ibis import BaseBackend
 
 
+class SaveMode(StrEnum):
+    """`SaveMode` is used to specify the expected behavior of saving a table."""
+
+    APPEND = auto()
+    OVERWRITE = auto()
+    ERROR = auto()
+    ERRORIFEXISTS = auto()
+    IGNORE = auto()
+
+
 class TableDataset(ConnectionMixin, AbstractDataset[ir.Table, ir.Table]):
     """`TableDataset` loads/saves data from/to Ibis table expressions.
 
@@ -28,14 +45,18 @@ class TableDataset(ConnectionMixin, AbstractDataset[ir.Table, ir.Table]):
             database: company.db
           save_args:
             materialized: table
+            mode: append
 
         motorbikes:
           type: ibis.TableDataset
           table_name: motorbikes
           connection:
             backend: duckdb
             database: company.db
-        ```
+          save_args:
+            materialized: view
+            mode: overwrite
+    ```
 
         Using the [Python API](https://docs.kedro.org/en/stable/catalog-data/advanced_data_catalog_usage/):
 
@@ -62,7 +83,7 @@ class TableDataset(ConnectionMixin, AbstractDataset[ir.Table, ir.Table]):
     DEFAULT_LOAD_ARGS: ClassVar[dict[str, Any]] = {}
     DEFAULT_SAVE_ARGS: ClassVar[dict[str, Any]] = {
         "materialized": "view",
-        "overwrite": True,
+        "mode": "overwrite",
     }
 
     _CONNECTION_GROUP: ClassVar[str] = "ibis"
@@ -109,7 +130,12 @@ def __init__(  # noqa: PLR0913
                 `create_{materialized}` method. By default, ``ir.Table``
                 objects are materialized as views. To save a table using
                 a different materialization strategy, supply a value for
-                `materialized` in `save_args`.
+                `materialized` in `save_args`. The `mode` parameter controls
+                the behavior when saving data:
+                - _"overwrite"_: Overwrite existing data in the table.
+                - _"append"_: Append contents of the new data to the existing table (does not overwrite).
+                - _"error"_ or _"errorifexists"_: Throw an exception if the table already exists.
+                - _"ignore"_: Silently ignore the operation if the table already exists.
             metadata: Any arbitrary metadata. This is ignored by Kedro,
                 but may be consumed by users or external plugins.
         """
@@ -134,6 +160,22 @@ def __init__(  # noqa: PLR0913
 
         self._materialized = self._save_args.pop("materialized")
 
+        # Handle mode/overwrite conflict.
+        if save_args and "mode" in save_args and "overwrite" in self._save_args:
+            raise ValueError("Cannot specify both 'mode' and deprecated 'overwrite'.")
+
+        # Map legacy overwrite if present.
+        if "overwrite" in self._save_args:
+            legacy = self._save_args.pop("overwrite")
+            # Remove any lingering 'mode' key from defaults to avoid
+            # leaking into writer kwargs.
+            del self._save_args["mode"]
+            mode = "overwrite" if legacy else "error"
+        else:
+            mode = self._save_args.pop("mode")
+
+        self._mode = SaveMode(mode)
+
     def _connect(self) -> BaseBackend:
         import ibis  # noqa: PLC0415
 
@@ -151,7 +193,21 @@ def load(self) -> ir.Table:
 
     def save(self, data: ir.Table) -> None:
         writer = getattr(self.connection, f"create_{self._materialized}")
-        writer(self._table_name, data, **self._save_args)
+        if self._mode == "append":
+            if not self._exists():
+                writer(self._table_name, data, overwrite=False, **self._save_args)
+            elif hasattr(self.connection, "insert"):
+                self.connection.insert(self._table_name, data, **self._save_args)
+            else:
+                raise DatasetError(
+                    f"The {self.connection.name} backend for Ibis does not support inserts."
+                )
+        elif self._mode == "overwrite":
+            writer(self._table_name, data, overwrite=True, **self._save_args)
+        elif self._mode in {"error", "errorifexists"}:
+            writer(self._table_name, data, overwrite=False, **self._save_args)
+        elif self._mode == "ignore" and not self._exists():
+            writer(self._table_name, data, overwrite=False, **self._save_args)
 
     def _describe(self) -> dict[str, Any]:
         load_args = deepcopy(self._load_args)
@@ -165,6 +221,7 @@ def _describe(self) -> dict[str, Any]:
             "load_args": load_args,
             "save_args": save_args,
             "materialized": self._materialized,
+            "mode": self._mode,
         }
 
     def _exists(self) -> bool:

kedro-datasets/pyproject.toml

@@ -11,6 +11,7 @@ description = "Kedro-Datasets is where you can find all of Kedro's data connecto
 requires-python = ">=3.10"
 license = {text = "Apache Software License (Apache 2.0)"}
 dependencies = [
+    "backports.strenum; python_version < '3.11'",
     "kedro>=1.0.0rc1, <2.0.0",
     "lazy_loader",
 ]

kedro-datasets/tests/ibis/test_table_dataset.py

@@ -1,6 +1,8 @@
 import duckdb
 import ibis
+import pandas as pd
 import pytest
+from kedro.io import DatasetError
 from packaging.version import Version
 from pandas.testing import assert_frame_equal
 
@@ -37,13 +39,15 @@ def connection_config(request, database):
 
 @pytest.fixture
 def table_dataset(database_name, connection_config, load_args, save_args):
-    return TableDataset(
+    ds = TableDataset(
         table_name="test",
         database=database_name,
         connection=connection_config,
         load_args=load_args,
         save_args=save_args,
     )
+    yield ds
+    getattr(ds._connection, f"drop_{ds._materialized}")("test", force=True)
 
 
 @pytest.fixture
@@ -77,9 +81,10 @@ def test_save_and_load(self, table_dataset, dummy_table, database):
         assert "test" in con.sql("SELECT * FROM duckdb_views").fetchnumpy()["view_name"]
 
     @pytest.mark.parametrize(
-        "connection_config", [{"backend": "polars"}], indirect=True
+        ("connection_config", "save_args"),
+        [({"backend": "polars"}, {"materialized": "table"})],
+        indirect=True,
     )
-    @pytest.mark.parametrize("save_args", [{"materialized": "table"}], indirect=True)
     def test_save_and_load_polars(
         self, table_dataset, connection_config, save_args, dummy_table
     ):
@@ -102,14 +107,135 @@ def test_exists(self, table_dataset, dummy_table):
         table_dataset.save(dummy_table)
         assert table_dataset.exists()
 
+    @pytest.mark.parametrize(
+        "save_args", [{"materialized": "table", "mode": "append"}], indirect=True
+    )
+    def test_save_mode_append(self, table_dataset, dummy_table):
+        """Saving with mode=append should add rows to an existing table."""
+        df1 = dummy_table
+        df2 = dummy_table
+
+        table_dataset.save(df1)
+        table_dataset.save(df2)
+
+        df1 = df1.execute()
+        df2 = df2.execute()
+        reloaded = table_dataset.load().execute()
+        assert len(reloaded) == len(df1) + len(df2)
+
+    @pytest.mark.parametrize(
+        "save_args",
+        [
+            {"materialized": "table", "mode": "error"},
+            {"materialized": "table", "mode": "errorifexists"},
+        ],
+        indirect=True,
+    )
+    def test_save_mode_error_variants(self, table_dataset, dummy_table):
+        """Saving with error/errorifexists should raise when table exists."""
+        table_dataset.save(dummy_table)
+        with pytest.raises(DatasetError, match='Table with name "test" already exists'):
+            table_dataset.save(dummy_table)
+
+    @pytest.mark.parametrize(
+        "save_args", [{"materialized": "table", "mode": "ignore"}], indirect=True
+    )
+    def test_save_mode_ignore(self, table_dataset, dummy_table):
+        """Saving with ignore should not change existing table."""
+        df1 = dummy_table
+        df2 = dummy_table
+
+        table_dataset.save(df1)
+        table_dataset.save(df2)
+        df1 = df1.execute()
+
+        reloaded = table_dataset.load().execute()
+        # Should remain as first save only
+        assert_frame_equal(reloaded.reset_index(drop=True), df1.reset_index(drop=True))
+
+    def test_unsupported_save_mode_raises(self, database_name, connection_config):
+        """Providing an unsupported save mode should raise a DatasetError."""
+        with pytest.raises(
+            ValueError, match="'unsupported_mode' is not a valid SaveMode"
+        ):
+            TableDataset(
+                table_name="unsupported_mode",
+                database=database_name,
+                connection=connection_config,
+                save_args={"materialized": "table", "mode": "unsupported_mode"},
+            )
+
+    def test_legacy_overwrite_conflict_raises(self, database_name, connection_config):
+        """Providing both mode and overwrite should raise a ValueError."""
+        with pytest.raises(ValueError):
+            TableDataset(
+                table_name="conflict",
+                database=database_name,
+                connection=connection_config,
+                save_args={
+                    "materialized": "table",
+                    "mode": "append",
+                    "overwrite": True,
+                },
+            )
+
+    @pytest.mark.parametrize(
+        ("connection_config", "save_args"),
+        [({"backend": "polars"}, {"materialized": "table", "mode": "append"})],
+        indirect=True,
+    )
+    def test_append_mode_no_insert_raises(self, table_dataset, dummy_table):
+        """Test that saving with mode=append on a backend without 'insert' raises DatasetError (polars backend)."""
+        # Save once to create the table
+        table_dataset.save(dummy_table)
+        # Try to append again, should raise DatasetError
+        with pytest.raises(DatasetError, match="does not support inserts"):
+            table_dataset.save(dummy_table)
+
+    @pytest.mark.parametrize(
+        "save_args",
+        [
+            {"materialized": "table", "overwrite": True},
+            {"materialized": "table", "overwrite": False},
+        ],
+        indirect=True,
+    )
+    def test_legacy_overwrite_behavior(self, table_dataset, save_args, dummy_table):
+        """Legacy overwrite should map to overwrite or error behavior."""
+        legacy_overwrite = save_args["overwrite"]
+        df2 = ibis.memtable(pd.DataFrame({"col1": [7], "col2": [8], "col3": [9]}))
+
+        table_dataset.save(dummy_table)  # First save should always work
+        if legacy_overwrite:
+            # Should overwrite existing table with new contents
+            table_dataset.save(df2)
+            df2 = df2.execute()
+            out = table_dataset.load().execute().reset_index(drop=True)
+            assert_frame_equal(out, df2.reset_index(drop=True))
+        else:
+            # Should raise on second save when table exists
+            with pytest.raises(DatasetError):
+                table_dataset.save(df2)
+
+    def test_describe_includes_backend_mode_and_materialized(self, table_dataset):
+        """_describe should expose backend, mode and materialized; nested args exclude database."""
+
+        desc = table_dataset._describe()
+
+        assert {"backend", "mode", "materialized"} <= desc.keys()
+        assert "database" in desc
+        # database key should not be duplicated inside nested args
+        assert "database" not in desc["load_args"]
+        assert "database" not in desc["save_args"]
+
     @pytest.mark.parametrize("load_args", [{"database": "test"}], indirect=True)
     def test_load_extra_params(self, table_dataset, load_args):
         """Test overriding the default load arguments."""
         for key, value in load_args.items():
             assert table_dataset._load_args[key] == value
 
     @pytest.mark.parametrize("save_args", [{"materialized": "table"}], indirect=True)
-    def test_save_extra_params(self, table_dataset, save_args, dummy_table, database):
+    def test_save_extra_params(self, table_dataset, dummy_table, database):
         """Test overriding the default save arguments."""
         table_dataset.save(dummy_table)