Is it possiible to change attribute name on db.Model kind? i have some field name created with dash (e.g. field-name) that resulting error.
class DataBulk(db.Model):
group_id = db.IntegerProperty()
group_name = db.StringProperty()
geo_pos = db.GeoPtProperty()
group-leader = db.StringProperty() <-----------error
imported = db.IntegerProperty(default=0)
Anyone can tell me what's wrong?
You must use valid Python names to define properties like that. Strictly speaking you can define the name that is stored in datastore, passing an argument "name" to the property:
class DataBulk(db.Model):
group_id = db.IntegerProperty()
group_leader = db.StringProperty(name='group-leader')
Related
I want to add an created_by and updated_by field to all my DB objects. I created a common model for this that will be used by most other objects. I have sorted out most obstacles so far. But the make migrations script ends with an error:
My model:
class CommonModel(models.Model):
"""Common fields that are shared among all models."""
created_by = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT,
editable=False, related_name="+")
updated_by = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT,
editable=False, related_name="+")
created_at = models.DateTimeField(auto_now_add=True,
editable=False)
updated_at = models.DateTimeField(auto_now=True,
editable=False)
class Meta:
abstract = True
class Tag(CommonModel):
"""Tag to be used for device type"""
name = models.CharField(max_length=255)
def __str__(self):
return self.name
The error I get is :
You are trying to add a non-nullable field 'created_by' to devicetype without a default; we can't do that (the database needs something to populate existing rows).
Please select a fix:
Provide a one-off default now (will be set on all existing rows with a null value for this column)
Quit, and let me add a default in models.py
The only "solution" I found searching the Internet was to define default='', run the makemigrations again and then manually edit the files afterwards to remove the default=''.
I cannot believe that this is the proper way to do this and that there is no solution for this yet.
You need to set a default value for created_at and update_at, since they are not null=True.
The message you get during migration is not an error. If you want to provide a default value, select fix 1., it should show the below prompt,
Please enter the default value now, as valid Python
The datetime and ` modules are available, so you can do e.g. timezone.now
Type 'exit' to exit this prompt
>>>
Here you can set the default value using the datetime or django.utils.timezone module.
I am trying to populate a table with data and am using Django's get_or_create method. Whenever I do this it will enter records into the database but at a certain record it will throw the above error. My queryset function is
r, created = Response.objects.get_or_create(
auth_user=auth_user,
name=surv_name,
organization=org_id,
category=category,
question=question,
present_order=present_order,
reference=reference,
quest_id=quest_id,
survey_id=survey_id
)
My response table is
class Response(models.Model):
auth_user = models.ForeignKey('AuthUser')
survey = models.ForeignKey('Survey')
name = models.CharField(max_length=50)
organization = models.ForeignKey('Organization')
tf_question_key = models.CharField(max_length=50)
category = models.CharField(max_length=25, blank=True, null=True)
question = models.CharField(max_length=2048)
quest_id = models.CharField(max_length=25)
present_order = models.IntegerField()
reference = models.CharField(max_length=20)
answer = models.CharField(max_length=2048)
remediation = models.CharField(max_length=2048, blank=True, null=True)
dt_started = models.DateTimeField(db_column='DT_Started',
auto_now_add=True) # Field name made lowercase.
dt_completed = models.DateTimeField(db_column='DT_COMPLETED',
auto_now_add=True) # Field name made lowercase.
class Meta:
managed = False
db_table = 'response'
and the traceback where the error is located is
organization <Organization: Individual Offices>
r <Response: Response object>
user_id 2
question ('Does your written policy include the follow-up process for significant outstanding checks, including, but not limited to, checks to recording clerk, checks to tax collector, hazard insurance checks, underwriter checks or checks for mortgage payoffs and any other high risk items? ( 2.03 k )')
present_order 21
survey_id 1
reference '2.03 (k)'
quest_id 27
created True
category 'Pillar II'
surv_name 'Compliance Benchmark'
org_id 1
auth_user <AuthUser: AuthUser object>
I can add records to the table by using
r = Response(
auth_user=auth_user,
name=surv_name,
organization=organization,
category=category,
question=question,
present_order=present_order,
reference=reference,
quest_id=quest_id,
survey_id=survey_id
)
r.save()
but I need to use the get_or_create method to avoid duplicating records. I am not sure why I can add records with the .save() method but not with get_or_create and also why with get_or_create it will add records up to a certain one and then fail. The only thing that is changing is the question, quest_id, present_order, and reference.
I am using python 3.4, django 1.8.4 and SQL Server 2014
Any insight would be greatly appreciated.
I ran into the same issue and turned on logging on sql server to see what was occurring. It looks like long text fields are being converted to ntext. This is then being compared to the nvarchar field causing the error.
The error is occurring during the SELECT within the get_or_create function. Instead of using get_or_create, query for your model with startswith. Using startswith performs a LIKE check which will work. I also added a length check on the field to ensure the fields will match instead of finding other rows with the same starting value.
from django.core.exceptions import ObjectDoesNotExist
from django.db.models.functions import Length
attrs = {
auth_user=auth_user,
name=surv_name,
organization=org_id,
category=category,
present_order=present_order,
reference=reference,
quest_id=quest_id,
survey_id=survey_id,
}
try:
r = Response.objects.annotate(
text_len=Length('question')
).get(
text_len__exact=len(question),
question__startswith=question,
**attrs
)
except ObjectDoesNotExist:
r = Response.objects.create(
question=question,
**attrs
)
I'm going in circles on getting the id of NDB Datastore.
I have setup the webapp2.RequestHandler to catch the email and get the ID. Basically my goal is to delete an entity, but if I pass the email address to get the ID of the entity, I'm stump, because it gives me results I was just getting. I used ID instead of key_name.
I tried finding the ID by querying via email, but it seems like using query does not have a method attribute to find the id.
def get(self,email):
user = users.get_current_user()
if user:
user_key = ndb.Key('UserPrefs',user.email())
contacts = Contact.query(Contact.email==email,ancestor=user_key)
self.response.write(contacts.id) # there is no attribute such as Contact.id
I tried to find the ID by getting the key, but when I displayed the key, it showed me whatever value I have in the email variable
def get(self,email):
user = users.get_current_user()
if user:
user_key = ndb.Key('UserPrefs',user.email())
contact_key = ndb.Key('Contact',email,parent=user_key)
self.response.write(contact_key.id())
Real Question: So, given that I do not have the ID, how do I find the correct ID inside an entity if I saved my entities via id and not key_name?
Here are the mixture of codes that I'm trying out.
def get(self,email):
user = users.get_current_user()
if user:
user_key = ndb.Key('UserPrefs',user.email())
contact_key = ndb.Key('Contact',email,parent=user_key)
contacts = Contact.query(Contact.email==email,ancestor=user_key)
contact = contacts.get()
contact_key.delete()
# self.response.write(contact.name) # this works
self.response.write(contact_key.id()) # this does not work because I do not have the entity id, and I'd like to get it blindfolded. Is there a way?
Here is my Model for Contact.
class Contact(ndb.Model):
name = ndb.StringProperty()
phone = ndb.StringProperty()
email = ndb.StringProperty()
dateCreated = ndb.DateTimeProperty(auto_now_add=True)
dateUpdated = ndb.DateTimeProperty(auto_now=True)
The docs state:
The identifier may be either a key "name" string assigned by the application or an integer numeric ID generated automatically by the Datastore.
Since you are defining the name property on your Contact class, this is used as the identifier. (You don't want that because in real world different users can have same names)
So if you want NDB to generate numeric IDs for your entities, rename the name property to something else, e.g. username.
Update: let's go step by step:
Problem with the first example is that you are trying to get id on the Query. Query class has no id property defined on it. You should call get() on it:
# get() or fetch() should be called on query to return some data
contacts = Contact.query(Contact.email==email,ancestor=user_key).get()
self.response.write(contacts.id) # there is no attribute such as Contact.id
Problem with the second piece of code is that you are just initialising a Key and providing email as id - the second param of constructor is the id and you are providing email as value. Hence you are getting the email out. Also, there is no database operation here.
Note: the identifiers, which are id, key, urlsafe, or value (for the query) should be passed from the HTTP Request by webapp2.RequestHandler from a parsed url or HTTP POST, GET, PUT, or DELETE.
If you do not have any identifiers or values passed from an HTTP request, it could be difficult to access the specific entity (or the record). So, it is important to take note to pass a form of identifier or value to access the specific entity (or the record in database terms).
So, you can do the following to get the id:
Access by value:
def get(self,email):
user = users.get_current_user()
if user:
user_key = ndb.Key('UserPrefs',user.email())
contacts = Contact.query(Contact.email==email,ancestor=user_key)
contact = contacts.get()
id = contact.key.id() # this access the entity id directly because you have the data.
self.response.write(id)
Access by urlsafe:
def get(self,urlString):
user = users.get_current_user()
if user:
contact_key = ndb.Key(urlsafe=urlString) #urlString refers to the key of contact
contact = contact_key.get()
id = contact.key.id() # this access the entity id directly because you have the data.
self.response.write(id)
Access by HTTP POST Request:
def post(self):
user = users.get_current_user()
if user:
user_key = ndb.Key('UserPrefs',user.email())
email = self.request.get('email')
contacts = Contact.query(Contact.email==email,ancestor=user_key)
contact = contacts.get()
id = contact.key.id() # this access the entity id directly because you have the data.
self.response.write(id)
I've got a simple User model, defined like so:
# models.py
from datetime import datetime
from myapp import db
class User(db.Model):
id = db.Column(db.Integer(), primary_key=True)
email = db.Column(db.String(100), unique=True)
password = db.Column(db.String(100))
date_updated = db.Column(db.DateTime())
def __init__(self, email, password, date_updated=None):
self.email = email
self.password = password
self.date_updated = datetime.utcnow()
When I create a new User object, my date_updated field gets set to the current time. What I'd like to do is make it so that whenever I save changes to my User object my date_updated field is set to the current time automatically.
I've scoured the documentation, but for the life of me I can't seem to find any references to this. I'm very new to SQLAlchemy, so I really have no prior experience to draw from.
Would love some feedback, thank you.
Just add server_default or default argument to the column fields:
created_on = db.Column(db.DateTime, server_default=db.func.now())
updated_on = db.Column(db.DateTime, server_default=db.func.now(), server_onupdate=db.func.now())
I prefer the {created,updated}_on column names. ;)
SQLAlchemy docs about column insert/update defaults.
[Edit]: Updated code to use server_default arguments in the code.
[Edit 2]: Replaced onupdate with server_onupdate arguments.
date_created = db.Column(db.DateTime, default=db.func.current_timestamp())
date_modified = db.Column(db.DateTime, default=db.func.current_timestamp(),
onupdate=db.func.current_timestamp())
My model
class BaseArticleModel(polymodel.PolyModel):
title = db.StringProperty()
created_at = db.DateProperty(auto_now_add=True)
updated_at = db.DateProperty(auto_now=True)
class News(BaseArticleModel):
body = db.TextProperty()
I need get rows by last month. I use interactive console. When to do filter like this
q = News.all().filter('created_at.month = ',datetime(2011,04,01).month)
print q[0].title
I get "IndexError: The query returned fewer than 1 results"
I was get something like your solution in the Google App Engine group.
class BaseArticleModel(polymodel.PolyModel):
title = db.StringProperty()
created_at = db.DateProperty(auto_now_add=True)
updated_at = db.DateProperty(auto_now=True)
#db.ComputedProperty
def CM(self):
return self.created_at.month
To query based on a month, I'd suggest adding an additional derived field to your model which is automatically updated when the object gets saved:
class BaseArticleModel(polymodel.PolyModel):
title = db.StringProperty()
created_at = db.DateProperty(auto_now_add=True)
updated_at = db.DateProperty(auto_now=True)
# will be auto-generated
created_at_month = db.IntegerProperty()
def put(self, *args, **kwargs):
self.created_at_month = self.created_at.month
super(BaseArticleModel, self).put(*args, **kwargs)
Edit: Re-reading your question, it looks like you're not really looking for all posts from a given month (e.g. October of any year), but rather just posts in a single month. If that's the case then you should be able to just revise your query to a simple comparison:
# get News posted in April, 2011
all_news = News.all()
all_news.filter('created_at >=', datetime(2011, 4, 1))
all_news.filter('created_at <', datetime(2011, 5, 1))
Edit #2: As noted by Nick below, overriding put() would be bad form, since it would only be effective when called as a bound method, and will NOT work with db.put() or other ways of saving to the datastore.