patito.Model.join

classmethod Model.join(other, how)

Dynamically create a new model compatible with an SQL Join operation.

For instance, ModelA.join(ModelB, how="left") will create a model containing all the fields of ModelA and ModelB, but where all fields of ModelB has been made Optional, i.e. nullable. This is consistent with the LEFT JOIN SQL operation making all the columns of the right table nullable.

Parameters

  • other (Type[Model]) – Another patito Model class.

  • how (Literal[‘inner’, ‘left’, ‘outer’, ‘asof’, ‘cross’, ‘semi’, ‘anti’]) – The type of SQL Join operation.

Return type

Type[Model]

Returns

A new model type compatible with the resulting schema produced by the given join operation.

Examples

>>> class A(Model):
...     a: int
...
>>> class B(Model):
...     b: int
...

>>> InnerJoinedModel = A.join(B, how="inner")
>>> InnerJoinedModel.columns
['a', 'b']
>>> InnerJoinedModel.nullable_columns
set()

>>> LeftJoinedModel = A.join(B, how="left")
>>> LeftJoinedModel.nullable_columns
{'b'}

>>> OuterJoinedModel = A.join(B, how="outer")
>>> sorted(OuterJoinedModel.nullable_columns)
['a', 'b']

>>> A.join(B, how="anti") is A
True