def update(self):
"""
updates a row.
This is a blind update call.
All validation and cleaning needs to happen
prior to calling this.
"""
if self.instance is None:
raise CQLEngineException("DML Query intance attribute is None")
assert type(self.instance) == self.model
null_clustering_key = False if len(self.instance._clustering_keys) == 0 else True
static_changed_only = True
statement = UpdateStatement(self.column_family_name, ttl=self._ttl, timestamp=self._timestamp,
conditionals=self._conditional, if_exists=self._if_exists)
for name, col in self.instance._clustering_keys.items():
null_clustering_key = null_clustering_key and col._val_is_null(getattr(self.instance, name, None))
updated_columns = set()
# get defined fields and their column names
for name, col in self.model._columns.items():
# if clustering key is null, don't include non static columns
if null_clustering_key and not col.static and not col.partition_key:
continue
if not col.is_primary_key:
val = getattr(self.instance, name, None)
val_mgr = self.instance._values[name]
if val is None:
continue
if not val_mgr.changed and not isinstance(col, columns.Counter):
continue
static_changed_only = static_changed_only and col.static
statement.add_update(col, val, previous=val_mgr.previous_value)
updated_columns.add(col.db_field_name)
if statement.assignments:
for name, col in self.model._primary_keys.items():
# only include clustering key if clustering key is not null, and non static columns are changed to avoid cql error
if (null_clustering_key or static_changed_only) and (not col.partition_key):
continue
statement.add_where(col, EqualsOperator(), getattr(self.instance, name))
self._execute(statement)
if not null_clustering_key:
# remove conditions on fields that have been updated
delete_conditionals = [condition for condition in self._conditional
if condition.field not in updated_columns] if self._conditional else None
self._delete_null_columns(delete_conditionals)
def update(self, **values):
"""
Performs an update on the row selected by the queryset. Include values to update in the
update like so:
.. code-block:: python
Model.objects(key=n).update(value='x')
Passing in updates for columns which are not part of the model will raise a ValidationError.
Per column validation will be performed, but instance level validation will not
(i.e., `Model.validate` is not called). This is sometimes referred to as a blind update.
For example:
.. code-block:: python
class User(Model):
id = Integer(primary_key=True)
name = Text()
setup(["localhost"], "test")
sync_table(User)
u = User.create(id=1, name="jon")
User.objects(id=1).update(name="Steve")
# sets name to null
User.objects(id=1).update(name=None)
Also supported is blindly adding and removing elements from container columns,
without loading a model instance from Cassandra.
Using the syntax `.update(column_name={x, y, z})` will overwrite the contents of the container, like updating a
non container column. However, adding `__<operation>` to the end of the keyword arg, makes the update call add
or remove items from the collection, without overwriting then entire column.
Given the model below, here are the operations that can be performed on the different container columns:
.. code-block:: python
class Row(Model):
row_id = columns.Integer(primary_key=True)
set_column = columns.Set(Integer)
list_column = columns.List(Integer)
map_column = columns.Map(Integer, Integer)
:class:`~cqlengine.columns.Set`
- `add`: adds the elements of the given set to the column
- `remove`: removes the elements of the given set to the column
.. code-block:: python
# add elements to a set
Row.objects(row_id=5).update(set_column__add={6})
# remove elements to a set
Row.objects(row_id=5).update(set_column__remove={4})
:class:`~cqlengine.columns.List`
- `append`: appends the elements of the given list to the end of the column
- `prepend`: prepends the elements of the given list to the beginning of the column
.. code-block:: python
# append items to a list
Row.objects(row_id=5).update(list_column__append=[6, 7])
# prepend items to a list
Row.objects(row_id=5).update(list_column__prepend=[1, 2])
:class:`~cqlengine.columns.Map`
- `update`: adds the given keys/values to the columns, creating new entries if they didn't exist, and overwriting old ones if they did
.. code-block:: python
# add items to a map
Row.objects(row_id=5).update(map_column__update={1: 2, 3: 4})
"""
if not values:
return
nulled_columns = set()
updated_columns = set()
us = UpdateStatement(self.column_family_name, where=self._where, ttl=self._ttl,
timestamp=self._timestamp, conditionals=self._conditional, if_exists=self._if_exists)
for name, val in values.items():
col_name, col_op = self._parse_filter_arg(name)
col = self.model._columns.get(col_name)
# check for nonexistant columns
if col is None:
raise ValidationError("{0}.{1} has no column named: {2}".format(self.__module__, self.model.__name__, col_name))
# check for primary key update attempts
if col.is_primary_key:
raise ValidationError("Cannot apply update to primary key '{0}' for {1}.{2}".format(col_name, self.__module__, self.model.__name__))
# we should not provide default values in this use case.
val = col.validate(val)
if val is None:
nulled_columns.add(col_name)
continue
us.add_update(col, val, operation=col_op)
updated_columns.add(col_name)
if us.assignments:
self._execute(us)
if nulled_columns:
delete_conditional = [condition for condition in self._conditional
if condition.field not in updated_columns] if self._conditional else None
ds = DeleteStatement(self.column_family_name, fields=nulled_columns,
where=self._where, conditionals=delete_conditional, if_exists=self._if_exists)
self._execute(ds)
def test_update_empty_set_removal_does_not_assign(self):
us = UpdateStatement('table')
us.add_update(Set(Text, db_field='a'), set(), 'remove')
self.assertFalse(us.assignments)
def test_update_list_append_with_empty_list(self):
us = UpdateStatement('table')
us.add_update(List(Text, db_field='a'), [], 'append')
self.assertFalse(us.assignments)
def test_update_set_add(self):
us = UpdateStatement('table')
us.add_update(Set(Text, db_field='a'), set((1,)), 'add')
self.assertEqual(six.text_type(us), 'UPDATE table SET "a" = "a" + %(0)s')
def test_update_set_add(self):
us = UpdateStatement('table')
us.add_update(Set(Text, db_field='a'), set((1,)), 'add')
self.assertEqual(six.text_type(us), 'UPDATE table SET "a" = "a" + %(0)s')
def test_update_list_append_with_empty_list(self):
us = UpdateStatement('table')
us.add_update(List(Text, db_field='a'), [], 'append')
self.assertFalse(us.assignments)
def test_update_empty_set_removal_does_not_assign(self):
us = UpdateStatement('table')
us.add_update(Set(Text, db_field='a'), set(), 'remove')
self.assertFalse(us.assignments)
async def async_update(self, **values):
if not values:
return
nulled_columns = set()
updated_columns = set()
us = UpdateStatement(
self.column_family_name,
where=self._where,
ttl=self._ttl,
timestamp=self._timestamp,
conditionals=self._conditional,
if_exists=self._if_exists,
)
for name, val in values.items():
col_name, col_op = self._parse_filter_arg(name)
col = self.model._columns.get(col_name)
# check for nonexistant columns
if col is None:
raise ValidationError(
"{0}.{1} has no column named: {2}".format(
self.__module__, self.model.__name__, col_name))
# check for primary key update attempts
if col.is_primary_key:
raise ValidationError(
"Cannot apply update to primary key '{0}' for {1}.{2}".
format(col_name, self.__module__, self.model.__name__))
if col_op == "remove" and isinstance(col, columns.Map):
if not isinstance(val, set):
raise ValidationError(
"Cannot apply update operation '{0}' on column '{1}' with value '{2}'. A set is required."
.format(col_op, col_name, val))
val = {v: None for v in val}
else:
# we should not provide default values in this use case.
val = col.validate(val)
if val is None:
nulled_columns.add(col_name)
continue
us.add_update(col, val, operation=col_op)
updated_columns.add(col_name)
if us.assignments:
await self._async_execute(us)
if nulled_columns:
delete_conditional = ([
condition for condition in self._conditional
if condition.field not in updated_columns
] if self._conditional else None)
ds = DeleteStatement(
self.column_family_name,
fields=nulled_columns,
where=self._where,
conditionals=delete_conditional,
if_exists=self._if_exists,
)
await self._async_execute(ds)
async def async_update(self):
"""
updates a row.
This is a blind update call.
All validation and cleaning needs to happen
prior to calling this.
"""
if self.instance is None:
raise CQLEngineException("DML Query intance attribute is None")
assert type(self.instance) == self.model
null_clustering_key = (False if len(self.instance._clustering_keys)
== 0 else True)
static_changed_only = True
statement = UpdateStatement(
self.column_family_name,
ttl=self._ttl,
timestamp=self._timestamp,
conditionals=self._conditional,
if_exists=self._if_exists,
)
for name, col in self.instance._clustering_keys.items():
null_clustering_key = null_clustering_key and col._val_is_null(
getattr(self.instance, name, None))
updated_columns = set()
# get defined fields and their column names
for name, col in self.model._columns.items():
# if clustering key is null, don't include non static columns
if (null_clustering_key and not col.static
and not col.partition_key):
continue
if not col.is_primary_key:
val = getattr(self.instance, name, None)
val_mgr = self.instance._values[name]
if val is None:
continue
if not val_mgr.changed and not isinstance(
col, columns.Counter):
continue
static_changed_only = static_changed_only and col.static
statement.add_update(col, val, previous=val_mgr.previous_value)
updated_columns.add(col.db_field_name)
if statement.assignments:
for name, col in self.model._primary_keys.items():
# only include clustering key if clustering key is not null,
# and non static columns are changed to avoid cql error
if (null_clustering_key
or static_changed_only) and (not col.partition_key):
continue
statement.add_where(col, EqualsOperator(),
getattr(self.instance, name))
await self._async_execute(statement)
if not null_clustering_key:
# remove conditions on fields that have been updated
delete_conditionals = ([
condition for condition in self._conditional
if condition.field not in updated_columns
] if self._conditional else None)
self._delete_null_columns(delete_conditionals)
def update(self, **values):
"""
Performs an update on the row selected by the queryset. Include values to update in the
update like so:
.. code-block:: python
Model.objects(key=n).update(value='x')
Passing in updates for columns which are not part of the model will raise a ValidationError.
Per column validation will be performed, but instance level validation will not
(i.e., `Model.validate` is not called). This is sometimes referred to as a blind update.
For example:
.. code-block:: python
class User(Model):
id = Integer(primary_key=True)
name = Text()
setup(["localhost"], "test")
sync_table(User)
u = User.create(id=1, name="jon")
User.objects(id=1).update(name="Steve")
# sets name to null
User.objects(id=1).update(name=None)
Also supported is blindly adding and removing elements from container columns,
without loading a model instance from Cassandra.
Using the syntax `.update(column_name={x, y, z})` will overwrite the contents of the container, like updating a
non container column. However, adding `__<operation>` to the end of the keyword arg, makes the update call add
or remove items from the collection, without overwriting then entire column.
Given the model below, here are the operations that can be performed on the different container columns:
.. code-block:: python
class Row(Model):
row_id = columns.Integer(primary_key=True)
set_column = columns.Set(Integer)
list_column = columns.List(Integer)
map_column = columns.Map(Integer, Integer)
:class:`~cqlengine.columns.Set`
- `add`: adds the elements of the given set to the column
- `remove`: removes the elements of the given set to the column
.. code-block:: python
# add elements to a set
Row.objects(row_id=5).update(set_column__add={6})
# remove elements to a set
Row.objects(row_id=5).update(set_column__remove={4})
:class:`~cqlengine.columns.List`
- `append`: appends the elements of the given list to the end of the column
- `prepend`: prepends the elements of the given list to the beginning of the column
.. code-block:: python
# append items to a list
Row.objects(row_id=5).update(list_column__append=[6, 7])
# prepend items to a list
Row.objects(row_id=5).update(list_column__prepend=[1, 2])
:class:`~cqlengine.columns.Map`
- `update`: adds the given keys/values to the columns, creating new entries if they didn't exist, and overwriting old ones if they did
.. code-block:: python
# add items to a map
Row.objects(row_id=5).update(map_column__update={1: 2, 3: 4})
"""
if not values:
return
nulled_columns = set()
updated_columns = set()
us = UpdateStatement(self.column_family_name, where=self._where, ttl=self._ttl,
timestamp=self._timestamp, conditionals=self._conditional, if_exists=self._if_exists)
for name, val in values.items():
col_name, col_op = self._parse_filter_arg(name)
col = self.model._columns.get(col_name)
# check for nonexistant columns
if col is None:
raise ValidationError("{0}.{1} has no column named: {2}".format(self.__module__, self.model.__name__, col_name))
# check for primary key update attempts
if col.is_primary_key:
raise ValidationError("Cannot apply update to primary key '{0}' for {1}.{2}".format(col_name, self.__module__, self.model.__name__))
# we should not provide default values in this use case.
val = col.validate(val)
if val is None:
nulled_columns.add(col_name)
continue
us.add_update(col, val, operation=col_op)
updated_columns.add(col_name)
if us.assignments:
self._execute(us)
if nulled_columns:
delete_conditional = [condition for condition in self._conditional
if condition.field not in updated_columns] if self._conditional else None
ds = DeleteStatement(self.column_family_name, fields=nulled_columns,
where=self._where, conditionals=delete_conditional, if_exists=self._if_exists)
self._execute(ds)