chore: remove database/duckdb support

pyproject.toml

@@ -136,4 +136,9 @@ module = ["tests.test_validators"]
 warn_unused_ignores = false
 
 [tool.ruff.lint]
-select = ["I"]
+select = ["E4", "E7", "E9", "F", "I"]
+ignore = []
+
+# Allow fix for all enabled rules (when `--fix`) is provided.
+fixable = ["ALL"]
+unfixable = []

src/patito/_pydantic/dtypes.py

@@ -1,16 +1,11 @@
-import itertools
 from enum import Enum
 from typing import (
     Any,
     Dict,
     FrozenSet,
     List,
-    Literal,
     Optional,
     Sequence,
-    Tuple,
-    cast,
-    get_args,
 )
 
 import polars as pl
@@ -70,8 +65,7 @@ class PydanticStringFormat(Enum):
 
 
 def parse_composite_dtype(dtype: DataTypeClass | DataType) -> str:
-    """for serialization, converts polars dtype to string representation
-    """
+    """for serialization, converts polars dtype to string representation"""
     if dtype in pl.NESTED_DTYPES:
         if dtype == pl.Struct or isinstance(dtype, pl.Struct):
             raise NotImplementedError("Structs not yet supported by patito")
@@ -156,7 +150,7 @@ def valid_polars_dtypes_for_annotation(
 
     Args:
         annotation (type[Any] | None): python type annotation
-    
+
     Returns:
         FrozenSet[DataTypeClass | DataType]: set of polars dtypes
     """