atoti.Column.default_value

property Column.default_value : Constant | 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[]",
...     "Object",
...     "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
...     }
... )
{'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,
 'Object': 'N/A',
 'String': 'N/A',
 'String[]': None,
 'ZonedDateTime': datetime.datetime(1970, 1, 1, 0, 0, tzinfo=TzInfo(0))}

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

​property Column.default_value : Constant | None

property Column.default_value : Constant | None