Saving instances

Creating new instances of a document

The easiest way of creating a new instance of a document is using Document.objects.create. Alternatively, you can create a new instance and then call save on it.

QuerySet.create(**kwargs)

Creates and saved a new instance of the document.

def handle_user_created(user):
    try:
        assert user.name == "Bernardo"
    finally:
        io_loop.stop()

def create_user():
    User.objects.create(name="Bernardo", callback=handle_user_created)

io_loop.add_timeout(1, create_user)
io_loop.start()

Document.save(**kwargs)

Creates or updates the current instance of this document.

def handle_user_created(user):
    try:
        assert user.name == "Bernardo"
    finally:
        io_loop.stop()

def create_user():
    user = User(name="Bernardo")
    user.save(callback=handle_user_created)

io_loop.add_timeout(1, create_user)
io_loop.start()

Updating instances

To update an instance, just make the needed changes to an instance and then call save.

Document.save(**kwargs)

Creates or updates the current instance of this document.

def handle_user_created(user):
    user.name = "Heynemann"
    user.save(callback=handle_user_updated)

def handle_user_updated(user):
    try:
        assert user.name == "Heynemann"
    finally:
        io_loop.stop()

def create_user():
    user = User(name="Bernardo")
    user.save(callback=handle_user_created)

io_loop.add_timeout(1, create_user)
io_loop.start()

Deleting instances

Deleting an instance can be easily accomplished by just calling delete on it:

Document.delete(**kwargs)

Deletes the current instance of this Document.

def handle_user_created(user):
    user.delete(callback=handle_user_deleted)

def handle_user_deleted(number_of_deleted_items):
    try:
        assert number_of_deleted_items == 1
    finally:
        io_loop.stop()

def create_user():
    user = User(name="Bernardo")
    user.save(callback=handle_user_created)

io_loop.add_timeout(1, create_user)
io_loop.start()

Sometimes, though, the requirements are to remove a few documents (or all of them) at a time. MotorEngine also supports deleting using filters in the document queryset.

QuerySet.delete(**kwargs)

Removes all instances of this document that match the specified filters (if any).

def handle_user_created(user):
    User.objects.filter(name="Bernardo").delete(callback=handle_users_deleted)

def handle_users_deleted(number_of_deleted_items):
    try:
        assert number_of_deleted_items == 1
    finally:
        io_loop.stop()

def create_user():
    user = User(name="Bernardo")
    user.save(callback=handle_user_created)

io_loop.add_timeout(1, create_user)
io_loop.start()

Bulk inserting instances

MotorEngine supports bulk insertion of documents by calling the bulk_insert method of a queryset with an array of documents:

QuerySet.bulk_insert(documents, callback=None, alias=None)

Inserts all documents passed to this method in one go.

def handle_users_inserted(users):
    try:
        assert len(users) == 2
        assert users[0]._id
        assert users[1]._id
    finally:
        io_loop.stop()

def create_users():
    users = [
        User(name="Bernardo"),
        User(name="Heynemann")
    ]
    User.objects.bulk_insert(users, callback=handle_users_inserted)

io_loop.add_timeout(1, create_users)
io_loop.start()