Basic Usage¶

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Query Syntax¶

StoredObject¶

class modularodm.storedobject.StoredObject(**kwargs)[source]¶

Base class to be used for models.

get_changed_fields(cached_data, storage_data)[source]¶

Get fields that differ between the cache_sandbox and the current object. Validation and after_save methods should only be run on diffed fields.

Parameters:	cached_data – Storage-formatted data from cache_sandbox storage_data – Storage-formatted data from object
Returns:	List of diffed fields

classmethod load(*args, **kwargs)[source]¶

Get a record by its primary key.

classmethod migrate_all()[source]¶

Migrate all records in this collection.

classmethod migrate(old, new, verbose=True, dry_run=False, rm_refs=True)[source]¶

Migrate record to new schema.

Parameters:	old – Record from original schema new – Record from new schema verbose – Print detailed info dry_run – Dry run; make no changes if true rm_refs – Remove references on deleted fields

validate_record()[source]¶

Apply record-level validation. Run on save.

save(*args, **kwargs)[source]¶

Save a record.

Parameters:	force (bool) – Save even if no fields have changed; used to update back-references
Returns:	List of changed fields

update_fields(**kwargs)[source]¶

Update multiple fields, specified by keyword arguments.

Example:

person.update(given_name='Fred', family_name='Mercury')

... is equivalent to ...

person.given_name = 'Fred'
person.family_name = 'Mercury'

Parameters:	**kwargs – field names and the values to set

classmethod find(*args, **kwargs)[source]¶

Parameters:	query – kwargs –
Returns:	an iterable of StoredObject instances

classmethod delegate(method, conflict=None, *args, **kwargs)[source]¶

Execute or queue a database action. Variable positional and keyword arguments are passed to the provided method.

Parameters:	method (function) – Method to execute or queue conflict (bool) – Potential conflict between cache_sandbox and backend, e.g., in the event of bulk updates or removes that bypass the cache_sandbox

classmethod start_queue()[source]¶

Start the queue. Between calling start_queue and commit_queue, all writes will be deferred to the queue.

classmethod clear_queue()[source]¶

Clear the queue.

classmethod cancel_queue()[source]¶

Cancel any pending actions. This method clears the queue and also clears caches if any actions are pending.

classmethod commit_queue()[source]¶

Commit all queued actions. If any actions fail, clear caches. Note: the queue will be cleared whether an error is raised or not.

classmethod subscribe(signal_name, weak=True)[source]¶

Parameters:	signal_name (str) – Name of signal to subscribe to; must be found in signals.py. weak (bool) – Create weak reference to callback
Returns:	Decorator created by Signal::connect_via
Raises:	ValueError if signal is not found

Example usage:

>>> @Schema.subscribe('before_save')
... def listener(cls, instance):
...     instance.value += 1

classmethod remove_one(*args, **kwargs)[source]¶

Remove an object, along with its references and back-references. Remove the object from the cache_sandbox and sets its _detached flag to True.

Parameters:	which – Object selector: Query, StoredObject, or primary key rm – Remove data from backend

classmethod remove(*args, **kwargs)[source]¶

Remove objects by query.

Parameters:	query – Query object

Backends¶

class modularodm.storage.base.Storage[source]¶

Abstract base class for storage objects. Subclasses (e.g. PickleStorage, MongoStorage, etc.) must define insert, update, get, remove, flush, and find_all methods.

translator = <modularodm.translators.DefaultTranslator object>¶

logger = <modularodm.storage.base.Logger object>¶

insert(this, *args, **kwargs)[source]¶

Insert a new record.

Parameters:	primary_name (str) – Name of primary key key – The value of the primary key value (dict) – The dictionary of attribute:value pairs

update(this, *args, **kwargs)[source]¶

Update multiple records with new data.

Parameters:	query – A query object. data (dict) – Dictionary of key:value pairs.

get(this, *args, **kwargs)[source]¶

Get a single record.

Parameters:	primary_name (str) – The name of the primary key. key – The value of the primary key.

remove(this, *args, **kwargs)[source]¶

Remove records.

flush(this, *args, **kwargs)[source]¶

Flush the database.

find_one(this, *args, **kwargs)[source]¶

Gets a single object from the collection.

If no matching documents are found, raises NoResultsFound. If >1 matching documents are found, raises MultipleResultsFound.

Params:	One or more Query or QuerySet objects may be passed
Returns:	The selected document

find(this, *args, **kwargs)[source]¶

Return a generator of query results. Takes optional by_pk keyword argument; if true, return keys rather than values.

Parameters:	query –
Returns:	a generator of StoredObject instances