MongoModel
Description
This project is a tiny ORM in python3 for mongodb.
Each database entry is a Document and each document has Fields
Getting started
git clone git@github.com:Chr0nos/mongomodel.git
virtualenv .venv
source .venv/bin/activate
pip install -r requirements.txtthen the in the code
import mongomodel
mongomodel.database.connect(host='something', db='test')
# now you can use the orm.Example
Create
To create a new document model you have to make a new class from Document
import mongomodel
class User(mongomodel.Document):
collection = 'user'
name = mongomodel.StringField(maxlen=255)
email = mongomodel.EmailField(maxlen=255)
level = mongomodel.IntegerField()then you can instanciate a new user in two ways:
user = User()
user.name = 'john doe'
user.level = 2
user.email = 'something@test.com'
user.save()or with the constructor:
user = User(name='john doe', email='something@test.com', level=2)
user.save()in case of an invalid model, example:
user.name = 123
user.save()an DocumentInvalidError will be raised.
Update
To update a document you just have to perform a document.save(), it will
update the document if it's already present in database.
Delete
Use document.delete()
Dynamic model creation
In some circumstancies you don't know the excat shape of a model at parsetime,
so it's possible to edit a model, the new field(s) has to be an instance of Field
user.specific_information = Field(value='whatever')Remove fields
you can delete the class attribute with
del user.nameTransform to dict
user.to_dict()Get all fields name for a document
user.fieldsreturns a list of str
Create a document from an other
cpy = user.copy()
cpy.kind = StringField(value='artist', maxlen='20')the copied document wil have it's own Fields
Load a document from it's ID
from bson import ObjectId
user = User.from_id(ObjectId('012345678'))Reset all fields to default
user.clear()Reload from database
user.refresh()Default fields
If you won't filter what kind of data can be set into a field, just use the
main class Field wich is allways considered as valid.
it's possible to have default values if the field stay at a None state
import mongomodel
from datetime import datetime
class Book(mongomodel.Document):
collection = 'book'
name = mongomodel.Field(default=lambda: '')
creation_date = mongomodel.Field(default=lambda: datetime.now().isoformat())I use function to prevent a useless call in case of no value provided.
Custom field
This is an example of a last updated field
from datetime import datetime
class LastUpdateField(mongomodel.Field):
def get(self):
return datetime.now().isoformat()the get method will be called each time you will call the attribute in the
document.
Custom field validation
class CustomField(mongomodel.Field):
def check(self):
# you can perform validations here.
# self.value = the current value
# self.get() = the value OR it's default if available
passExtra fields from database
All fields that are not defined into the model/document will be available in readonly.
Create many documents at once
books: List[Book] = [
Book(name='mongodb'),
Book(name='something'),
...
]
Book.insert_many(books)At this point all inserted (valids) book will have an _id property,
In case of invalid documents, no errors will be raised but the document will be
ignored.
QuerySet
All Document has a object attribute (created by a metaclass factory), wich
is a QuerySet instance pointing on the current model
with the User example
from examples.user import User, mongomodel
# setup the database
mongomodel.database.connect(host='127.0.0.1', db='test')
# get all users, the .all() will iterate over ALL results and put them in a list
User.objects.all()
# to iterate in more efficient way just iter over the `QuerySet` object
for user in User.objects:
print(user)
# search for all admin user with age higher than 30 years old
# the .filter expression return a `QuerySet` object, so you can chain them
User.objects.filter(is_admin=True, age__gt=30)
User.objects.filter(is_admin=True).exclude(age__gte=30)
# Both expressions does the same here.
# To see what a query will look like you can access to the .query parameter of
# the queryset
User.objects.filter(is_admin__exists=True).query
# will give us:
{'is_admin': {'$exists': True}}Ordering
you can also use the .sort method in QuerySet, the sort mehtod take a list or
a tupple of str like
qs = User.objects.sort(('-username', 'age'))
