Queryset

class yadm.queryset.BaseQuerySet(db, document_class, *, cache=None, criteria=None, projection=None, sort=None, slice=None, batch_size=None, collection_params=None)

Query builder.

Parameters:
  • db –
  • document_class –
  • cache –
  • criteria (dict) –
  • projection (dict) –
  • sort (list) –
  • slice (slice) –
  • collection_params (dict) –
batch_size(batch_size)

Setup batch size to cursor for this queryset.

cache

Queryset cache object.

copy(*, cache=None, criteria=None, projection=None, sort=None, slice=None, batch_size=None, collection_params=None)

Copy queryset with new parameters.

Only keywords arguments is alowed. Parameters simply replaced with given arguments.

Parameters:
  • cache –
  • criteria (dict) –
  • projection (dict) –
  • sort (list) –
  • slice (slice) –
  • collection_params (dict) –
Returns:

new yadm.queryset.QuerySet object
fields(*fields)

Get only setted fields.

Update projection with fields.

Parameters:fields (str) –
Returns:new yadm.queryset.QuerySet 
qs('field', 'field2')
fields_all()

Clear projection.

find(criteria=None, projection=None)

Return queryset copy with new criteria and projection.

Parameters:
  • criteria (dict) – update queryset’s criteria
  • projection (dict) – set queryset’s projection
Returns:

new yadm.queryset.QuerySet

 
qs({'field': {'$gt': 3}}, {'field': True})
read_preference(read_preference)

Setup readPreference.

Return new QuerySet instance.

Deprecated since 1.4.0. Use collection_params argument in copy.

read_primary(preferred=False)

Return queryset with setupd read concern for primary.

If preferred argument is True, PrimaryPreferred is used else Primary.

sort(*sort)

Return queryset with sorting.

Parameters:sort (tuples) – tuples with two items: (‘field_name’, sort_order_as_int). 
qs.sort(('field_1', 1), ('field_2', -1))
class yadm.queryset.NotFoundBehavior

An enumeration.

exception yadm.queryset.NotFoundError
class yadm.queryset.QuerySet(db, document_class, *, cache=None, criteria=None, projection=None, sort=None, slice=None, batch_size=None, collection_params=None)
bulk()

Return map {id: object}.

Returns:dict
count()

Count documents in queryset.

Returns:int
distinct(field)

Distinct query.

Parameters:field (str) – field for distinct
Returns:list with result data
find_and_modify(update=None, *, upsert=False, full_response=False, new=False, **kwargs)

Execute $findAndModify query.

Parameters:
  • update (dict) – see second argument to update()
  • upsert (bool) – insert if object doesn’t exist (default False)
  • full_response (bool) – return the entire response object from the server (default False)
  • new – return updated rather than original object (default False)
  • kwargs – any other options the findAndModify command supports can be passed here
Returns:

yadm.documents.Document or None
find_in(comparable, field='_id', *, not_found=<NotFoundBehavior.SKIP: 'skip'>)

Build ordered $in-query.

Creates a query of the form {field: {‘$in’: comparable}} and returns the generator of documents with the same order as an elements in the argument ‘comparable’.

Parameters:
  • comparable (list) – values for compare in a query
  • field (str) – field name of the document for comparison
  • not_found – flag determines the behavior if the document with the specified value is not found
Returns:

generator of docs
not_found argument can take the following values:
‘none’: If a document can not be found then a generator
will return None.
‘skip’: if a document can not be found then a generator
will pass element.
‘error’: if a document can not be found then a generator
raise yadm.queryset.DocNotFoundError exception.
find_one(criteria=None, projection=None, *, exc=None)

Find and return only one document.

Parameters:
  • criteria (dict) – update queryset’s criteria
  • projection (dict) – update queryset’s projection
  • exc (Exception) – raise given exception if not found
Returns:

yadm.documents.Document or None

 
qs({'field': {'$gt': 3}}, {'field': True})
ids()

Return all objects ids from queryset.

join(*field_names)

Create yadm.Join object, join field_names and return it.

Parameters:fields_names (str) – fields for join
Returns:new yadm.join.Join
Next algorithm for join:
  1. Get all documents from queryset;
  2. Aggegate all ids from requested fields;
  3. Make $in queries for get joined documents;
  4. Bind joined documents to objects from first queryset;

Join object is instance of abc.Sequence.

remove(*, multi=True)

Remove documents in queryset.

Parameters:multi (bool) – if False, remove only first finded document (default True)
update(update, *, multi=True, upsert=False)

Update documents in queryset.

Parameters:
  • update (dict) – update query
  • multi (bool) – update all matched documents (default True)
  • upsert (bool) – insert if not found (default False)
Returns:

update result
with_id(_id)

Find document with id.

This method is deprecated. Use find_one.

Parameters:_id – id of searching document
Returns:yadm.documents.Document or None