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Session: Deleting Entities
Entities can be marked for deletion by using the delete() method, but will not be removed from the server until save_changes() is called.
Syntax
def delete(self, key_or_entity: Union[str, object], expected_change_vector: Optional[str] = None) -> None:
...| Parameters | ||
|---|---|---|
| key_or_entity | str or object |
ID of the document or instance of the entity to delete |
| expected_change_vector | str |
a change vector to use for concurrency checks |
Example I
employee = session.load("employees/1")
session.delete(employee)
session.save_changes()Concurrency on Delete
If use_optimistic_concurrency is set to 'True' (default 'False'), the delete() method will use loaded 'employees/1' change vector for concurrency check and might throw ConcurrencyException.
Example II
session.delete("employees/1")
session.save_changes()Concurrency on Delete
The delete() method will not do any change vector based concurrency checks because the change vector for 'employees/1' is unknown.
Information
If entity is not tracked by session, then executing:
session.delete("employees/1")is equal to doing:
session.advanced.defer(DeleteCommandData("employees/1", change_vector=None))Change Vector in DeleteCommandData
In this sample the change vector is None - this means that there will be no concurrency checks. A not-None and valid change vector value will trigger a concurrency check.
You can read more about defer operations here.
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