mongoengine

I'm using mongoDB (mongoHQ) in my Flask app (mongoengine). I have a Document that looks like this: {items: [{id: 1}, {id: 2}, {id: 3}]} Is there a way to to reach, for example, the dict with id: 1 in a single query ? Currently I'm looping through the items list with a next() statement and I was hoping for a wiser solution. Thanks I'm not familiar with MongoEngine, but the $ projection operator can filter an array to show only the matched element. In the Mongo shell: > db.foo.insert({"items": [{"id": 1}, {"id": 2}, {"id": 3}]}) > db.foo.find({'items.id': 1}, {'items.$': true}) { "_id" :

Based on this tutorial I am trying to create a form to get a few measurements. It seems that the part to display the data is working but when using the model_form command to generate the input form it breaks with this error: File "/myproject/lib/python3.4/site-packages/flask_mongoengine/wtf/orm.py", line 49, in convert 'description': field.help_text or '', AttributeError: 'ObjectIdField' object has no attribute 'help_text' The error happens on this line of my code: form_cls = model_form(Measurement, exclude=('id', 'created_at', 'comments')) This is my view.py code: from flask import Blueprint,

If I have these models: class Sub(EmbeddedDocument): name = StringField() class Main(Document): subs = ListField(EmbeddedDocumentField(Sub)) I want to have a query that returns the Mains, with the subs being filtered by name existing Main.objects.filter(subs__name__exists=True) This returns the correct Mains, but the Subs are always the entire list, not a subset. How can I get only the subset? Do I need to rely on list comprehensions? MongoDB doesn't support exactly this operation that you're requesting, and therefore neither does Mongoengine. You can perform slicing operations on arrays

Why does mongoengine add _types and _cls fields to every document of a collection. Both of them are a (key, value) pair and both of them contain the name of the document's model class. The only difference is _types value is a list and I assume it can have multiple model class names if there is involved some inheritance. However the question is: why do I need them to exist in every document within a collection when all the documents will have the same values for both fields? Crazyshezy Mongoengine allows Document Inheritance. When defining a class a meta attribute allow_inheritance is used to

for example.. class Page(Document) tags = ListField(StringField()) In this case, we can find out a value in the tags list like this. Page.objects(tags='coding') if tags are like ['coding', 'x', 'y'], then the document will be matched... but My question is how I can find out the value not in the listfield. my incorrect code would be.. Page.objects(tags!='coding') or Page.objects(tags__not = 'coding') or Page.objects(tags__not__in = 'coding') but.. they don't simply work.. how can I query a document that does not have a given value in a ListField? To find any pages that don't have the tags

Let's take for example a blog post where a unique slug is generated from the post's title: sample_blog_post. Instead of storing a mongo ObjectId as the _id, say you store the slug in the _id. Besides the obvious case where the slug may change if the title changes, are there major disadvantages in terms of performance by using a string instead of a numerical _id? This could become problematic if, say, the number of posts became very large, say, over a million. But if the number of posts was relatively low, say, 2000, would it make much of a difference? So far the only thing about the ObjectId