atoti.Column.default_value

property Column.default_value: bool | int | float | date | datetime | time | Sequence[bool] | Sequence[int] | Sequence[float] | Sequence[str] | str | None

Value used to replace None inserted values.

The default value can either be:

• None:

  >>> none_default_value_table = session.create_table(
  ...     "None",
  ...     data_types={"ZonedDateTime": "ZonedDateTime"},
  ...     default_values={"ZonedDateTime": None},
  ... )
  >>> none_default_value_table["ZonedDateTime"].default_value
  

• a value matching the column’s data_type:

  >>> from datetime import datetime
  >>> from zoneinfo import ZoneInfo
  >>> homogeneous_default_value_table = session.create_table(
  ...     "Homogeneous",
  ...     data_types={"ZonedDateTime": "ZonedDateTime"},
  ...     default_values={
  ...         "ZonedDateTime": datetime(
  ...             2025,
  ...             2,
  ...             13,
  ...             20,
  ...             58,
  ...             42,
  ...             tzinfo=ZoneInfo("America/New_York"),
  ...         )
  ...     },
  ... )
  >>> homogeneous_default_value_table["ZonedDateTime"].default_value
  datetime.datetime(2025, 2, 13, 20, 58, 42, tzinfo=zoneinfo.ZoneInfo(key='America/New_York'))
  >>> session.create_table(  
  ...     "Heterogeneous",
  ...     data_types={"ZonedDateTime": "ZonedDateTime"},
  ...     default_values={
  ...         # Stringified ZonedDateTimes are not accepted.
  ...         "ZonedDateTime": "2025-02-13T20:58:42-05:00[America/New_York]"
  ...     },
  ... )
  Traceback (most recent call last):
      ...
  atoti._graphql_client.exceptions.GraphQLClientGraphQLMultiError: Coercion from STRING to ZONED_DATE_TIME is not supported. ...
  >>> session.create_table(  
  ...     "Heterogeneous",
  ...     data_types={"ZonedDateTime": "ZonedDateTime"},
  ...     default_values={
  ...         # `"N/A"` is not accepted either.
  ...         "ZonedDateTime": "N/A"
  ...     },
  ... )
  Traceback (most recent call last):
      ...
  atoti._graphql_client.exceptions.GraphQLClientGraphQLMultiError: Coercion from STRING to ZONED_DATE_TIME is not supported. ...
  >>> session.create_table(  
  ...     "Heterogeneous",
  ...     data_types={"ZonedDateTime": "ZonedDateTime"},
  ...     default_values={
  ...         # ZonedDateTime values must have a zone info.
  ...         "ZonedDateTime": datetime(2025, 2, 13, 20, 58, 42)
  ...     },
  ... )
  Traceback (most recent call last):
      ...
  atoti._graphql_client.exceptions.GraphQLClientGraphQLMultiError: Coercion from LOCAL_DATE_TIME to ZONED_DATE_TIME is not supported. ...
  

Each data type has its own default default_value value:

>>> import pprint
>>> all_data_types = [
...     "boolean",
...     "boolean[]",
...     "double",
...     "double[]",
...     "float",
...     "float[]",
...     "int",
...     "int[]",
...     "LocalDate",
...     "LocalDateTime",
...     "LocalTime",
...     "long",
...     "long[]",
...     "String",
...     "String[]",
...     "ZonedDateTime",
... ]
>>> all_data_types_table = session.create_table(
...     "All",
...     data_types={data_type: data_type for data_type in all_data_types},
... )
>>> pprint.pp(
...     {
...         column_name: all_data_types_table[column_name].default_value
...         for column_name in all_data_types_table
...     },
...     sort_dicts=False,
... )
{'boolean': False,
 'boolean[]': None,
 'double': None,
 'double[]': None,
 'float': None,
 'float[]': None,
 'int': None,
 'int[]': None,
 'LocalDate': datetime.date(1970, 1, 1),
 'LocalDateTime': datetime.datetime(1970, 1, 1, 0, 0),
 'LocalTime': datetime.time(0, 0),
 'long': None,
 'long[]': None,
 'String': 'N/A',
 'String[]': None,
 'ZonedDateTime': datetime.datetime(1970, 1, 1, 0, 0, tzinfo=TzInfo(UTC))}

Columns part of the table keys cannot have None as their default value. Key columns with:

• a numeric scalar data type default to 0:

  >>> numeric_scalar_data_types = [
  ...     "double",
  ...     "float",
  ...     "int",
  ...     "long",
  ... ]
  >>> numeric_scalar_data_types_table = session.create_table(
  ...     "Numeric scalar",
  ...     data_types={
  ...         data_type: data_type for data_type in numeric_scalar_data_types
  ...     },
  ...     keys=numeric_scalar_data_types,
  ... )
  >>> {
  ...     column_name: numeric_scalar_data_types_table[
  ...         column_name
  ...     ].default_value
  ...     for column_name in numeric_scalar_data_types_table
  ... }
  {'double': 0.0, 'float': 0.0, 'int': 0, 'long': 0}
  >>> numeric_scalar_data_types_table += (None, None, None, None)
  >>> numeric_scalar_data_types_table.head()
  Empty DataFrame
  Columns: []
  Index: [(0.0, 0.0, 0, 0)]
  

• an array data type must have their default value specified:

  >>> array_data_types = ["int[]", "long[]", "float[]", "double[]"]
  >>> session.create_table(
  ...     "Array",
  ...     data_types={data_type: data_type for data_type in array_data_types},
  ...     keys=array_data_types,
  ... )
  Traceback (most recent call last):
      ...
  atoti._graphql_client.exceptions.GraphQLClientGraphQLMultiError: Cannot make a int[] non-nullable because there is no global default value defined for this type. You should manually define a default value.
  >>> array_data_types_table = session.create_table(
  ...     "Array",
  ...     data_types={data_type: data_type for data_type in array_data_types},
  ...     default_values={
  ...         "int[]": [1],
  ...         "long[]": [2],
  ...         "float[]": [3.0],
  ...         "double[]": [4.0],
  ...     },
  ...     keys={"int[]"},
  ... )
  >>> {
  ...     column_name: array_data_types_table[column_name].default_value
  ...     for column_name in array_data_types_table
  ... }
  {'int[]': (1,), 'long[]': (2,), 'float[]': (3.0,), 'double[]': (4.0,)}
  >>> array_data_types_table += (None, None, None, None)
  >>> array_data_types_table.head()
        long[] float[] double[]
  int[]
  [1]      [2]   [3.0]    [4.0]
  

Changing the default value from:

• None to something else affects both the past None values and the future ones:

  >>> table = session.create_table(
  ...     "Change",
  ...     data_types={
  ...         "int[]": "int[]",
  ...         "long[]": "long[]",
  ...         "float": "float",
  ...         "String": "String",
  ...     },
  ...     default_values={
  ...         "int[]": [1],
  ...         "long[]": None,
  ...         "float": None,
  ...         "String": None,
  ...     },
  ...     keys={"int[]"},
  ... )
  >>> table += (None, None, None, None)
  >>> table["int[]"].default_value = [2]
  >>> table["long[]"].default_value = [3, 4, 5]
  >>> table["float"].default_value = 6.0
  >>> table["String"].default_value = "seven"
  >>> {column_name: table[column_name].default_value for column_name in table}
  {'int[]': (2,), 'long[]': (3, 4, 5), 'float': 6.0, 'String': 'seven'}
  >>> table += (None, None, None, None)
  >>> table.head().sort_index()
            long[]  float String
  int[]
  [1]    [3, 4, 5]    6.0  seven
  [2]    [3, 4, 5]    6.0  seven
  

• non-None to something else does not affect the past values:

  >>> table["int[]"].default_value = [8]
  >>> table["long[]"].default_value = [9, 10, 11]
  >>> table["float"].default_value = 12.0
  >>> table["String"].default_value = "thirteen"
  >>> table += (None, None, None, None)
  >>> table.head().sort_index()
              long[]  float    String
  int[]
  [1]      [3, 4, 5]    6.0     seven
  [2]      [3, 4, 5]    6.0     seven
  [8]    [9, 10, 11]   12.0  thirteen
  

Changing the default value from non-None to None is impossible both:

• for key columns:

  >>> table["int[]"].default_value = None
  Traceback (most recent call last):
      ...
  atoti._graphql_client.exceptions.GraphQLClientGraphQLMultiError: Cannot define a null default value for a non-nullable type.
  >>> table["int[]"].default_value
  (8,)
  

• and non-key columns:

  >>> table["float"].default_value = None
  Traceback (most recent call last):
      ...
  atoti._graphql_client.exceptions.GraphQLClientGraphQLMultiError: Cannot define a null default value for a non-nullable type.
  >>> table["float"].default_value
  12.0