diff --git a/src/safeds/data/tabular/containers/_column.py b/src/safeds/data/tabular/containers/_column.py
index 6c7b790fa..85edd4ba5 100644
--- a/src/safeds/data/tabular/containers/_column.py
+++ b/src/safeds/data/tabular/containers/_column.py
@@ -112,8 +112,8 @@ def __init__(
 
         # Implementation
         self._name: str = name
-        self._lazy_frame: pl.LazyFrame = pl.LazyFrame(data, schema={name: dtype}, strict=False)
-        self.__series_cache: pl.Series | None = None
+        self.__series_cache: pl.Series | None = pl.Series(name, data, dtype=dtype, strict=False)
+        self._lazy_frame: pl.LazyFrame = self.__series_cache.to_frame().lazy()
 
     def __contains__(self, value: object) -> bool:
         import polars as pl
diff --git a/src/safeds/data/tabular/query/_lazy_string_operations.py b/src/safeds/data/tabular/query/_lazy_string_operations.py
index cb9a2790a..c5750d48c 100644
--- a/src/safeds/data/tabular/query/_lazy_string_operations.py
+++ b/src/safeds/data/tabular/query/_lazy_string_operations.py
@@ -3,7 +3,7 @@
 from typing import TYPE_CHECKING
 
 from safeds._utils import _structural_hash
-from safeds._validation import _convert_and_check_datetime_format
+from safeds._validation import _convert_and_check_datetime_format, _check_bounds, _ClosedBound
 from safeds.data.tabular.containers._lazy_cell import _LazyCell
 
 from ._string_operations import StringOperations
@@ -75,9 +75,12 @@ def substring(
         start: _ConvertibleToIntCell = 0,
         length: _ConvertibleToIntCell = None,
     ) -> Cell[str | None]:
+        if isinstance(length, int):
+            _check_bounds("length", length, lower_bound=_ClosedBound(0))
+
         return _LazyCell(self._expression.str.slice(start, length))
 
-    def to_date(self, *, format: str | None = None) -> Cell[datetime.date | None]:
+    def to_date(self, *, format: str | None = "iso") -> Cell[datetime.date | None]:
         if format == "iso":
             format = "%F"  # noqa: A001
         elif format is not None:
@@ -85,7 +88,7 @@ def to_date(self, *, format: str | None = None) -> Cell[datetime.date | None]:
 
         return _LazyCell(self._expression.str.to_date(format=format, strict=False))
 
-    def to_datetime(self, *, format: str | None = None) -> Cell[datetime.datetime | None]:
+    def to_datetime(self, *, format: str | None = "iso") -> Cell[datetime.datetime | None]:
         if format == "iso":
             format = "%+"  # noqa: A001
         elif format is not None:
@@ -99,7 +102,7 @@ def to_int(self, *, base: _ConvertibleToIntCell = 10) -> Cell[int | None]:
     def to_lowercase(self) -> Cell[str | None]:
         return _LazyCell(self._expression.str.to_lowercase())
 
-    def to_time(self, *, format: str | None = None) -> Cell[datetime.time | None]:
+    def to_time(self, *, format: str | None = "iso") -> Cell[datetime.time | None]:
         if format == "iso":
             format = "%T"  # noqa: A001
         elif format is not None:
diff --git a/src/safeds/data/tabular/query/_string_operations.py b/src/safeds/data/tabular/query/_string_operations.py
index 0284d6029..6b99afe59 100644
--- a/src/safeds/data/tabular/query/_string_operations.py
+++ b/src/safeds/data/tabular/query/_string_operations.py
@@ -303,7 +303,7 @@ def substring(
 
     # TODO: add format parameter + document
     @abstractmethod
-    def to_date(self, *, format: str | None = None) -> Cell[datetime.date | None]:
+    def to_date(self, *, format: str | None = "iso") -> Cell[datetime.date | None]:
         """
         Convert the string value in the cell to a date.
 
@@ -331,7 +331,7 @@ def to_date(self, *, format: str | None = None) -> Cell[datetime.date | None]:
 
     # TODO: add format parameter + document
     @abstractmethod
-    def to_datetime(self, *, format: str | None = None) -> Cell[datetime.datetime | None]:
+    def to_datetime(self, *, format: str | None = "iso") -> Cell[datetime.datetime | None]:
         """
         Convert the string value in the cell to a datetime.