atoti.Session.create_table()#

Session.create_table(name, *, types, keys=frozenset({}), partitioning=None, default_values={}, **kwargs)#

Create an empty table with columns of the given types.

Parameters:

name (str) – The name of the table.
types (Mapping[str, DataType]) – The table column names and their corresponding data type.
keys (Set[str] | Sequence[str]) –
The columns that will become keys of the table.

If a Set is given, the keys will be ordered as the table columns.
partitioning (str | None) –
The description of how the data will be split across partitions of the table.

Default rules:
- Only non-joined tables are automatically partitioned.
- Tables are automatically partitioned by hashing their key columns. If there are no key columns, all the dictionarized columns are hashed.
- Joined tables can only use a sub-partitioning of the table referencing them.
- Automatic partitioning is done modulo the number of available cores.
Example

modulo4(country) splits the data across 4 partitions based on the country column’s dictionarized value.
default_values (Mapping[str, bool | int | float | date | datetime | time | Sequence[bool] | Sequence[int] | Sequence[float] | Sequence[str] | str | None]) – Mapping from column name to column default_value.

Return type:

Example

>>> from datetime import date
>>> table = session.create_table(
...     "Product",
...     keys={"Date", "Product"},
...     types={"Date": tt.LOCAL_DATE, "Product": tt.STRING, "Quantity": tt.DOUBLE},
... )
>>> table.head()
Empty DataFrame
Columns: [Quantity]
Index: []
>>> table.append(
...     (date(2021, 5, 19), "TV", 15.0),
...     (date(2022, 8, 17), "Car", 2.0),
... )
>>> table.head()
                    Quantity
Date       Product
2021-05-19 TV           15.0
2022-08-17 Car           2.0

Inserting a row with the same key values as an existing row replaces the latter:

>>> table += (date(2021, 5, 19), "TV", 8.0)
>>> table.head()
                    Quantity
Date       Product
2021-05-19 TV            8.0
2022-08-17 Car           2.0