Maybe i have an understanding problem. I try to make 2 tabeles in one database. But additionaly i need to have some temporary values in one class that i doen´t want to write to the database.
I try to switch to peewee and read the dokumentation but i find no solution at my own.
without peewee i would make an init method where i write my attributes. But where did i have to write them now?
from peewee import *
import datetime
db = SqliteDatabase('test.db', pragmas={'foreign_keys': 1})
class BaseModel(Model):
class Meta:
database = db
class Sensor(BaseModel):
id = IntegerField(primary_key=True)
sort = IntegerField()
name = TextField()
#def __init__(self):
#self.sometemporaryvariable = "blabla"
def meineparameter(self, hui):
self.hui = hui
print(self.hui)
class Sensor_measure(BaseModel):
id = ForeignKeyField(Sensor, backref="sensorvalues")
timestamp = DateTimeField(default=datetime.datetime.now)
value = FloatField()
class Meta:
primary_key = CompositeKey("id", "timestamp")
db.connect()
db.create_tables([Sensor_measure, Sensor])
sensor1 = Sensor.create(id=2, sort=20, name="Sensor2")
#sensor1.sometemporaryvariable = "not so important to write to the database"
sensor1.save()
Remember to call super() whenever overriding a method in a subclass:
class Sensor(BaseModel):
id = IntegerField(primary_key=True)
sort = IntegerField()
name = TextField()
def __init__(self, **kwargs):
self.sometemporaryvariable = "blabla"
super().__init__(**kwargs)
Related
I have a very big model in models.py:
simplified version is:
class MyModel(models.Model):
item_1 = models.FloatField(null=True, blank=True)
...
item_20 = models.FloatField(null=True, blank=True)
in views.py:
def form_valid(self, form_class):
instance = form_class.save(commit=False)
for i in range(1, 20):
name = 'item_' + str(i)
instance.name = i
With this the field name 'item_1' ... to 'item_20' in instance is not recogniced. Instead 'name' is added to instance like other new field...
How can I iterate and save my model?
Any suggestion?
Thanks!!!
You should probably use setattr in order to loop through the fields and set the values in them. Try this:
def form_valid(self, form_class):
instance = form_class.save(commit=False)
for i in range(1, 20):
name = 'item_' + str(i)
setattr(instance, name, value) # Where value is the data you wanted to save in the field `name`
Similary user getattr() to get the data by looping through the class instance.
I am using Angular and Bootstrap to serve my forms. If a user uploads an image, Angular serves it in the "data:" format, but Django is looking for a file type. I have fixed this issue by overriding both perform_authentication (To modify the image to a file) and perform_create (to inject my user_id). Is there a better way to override?
I'd rather not override my view. I'd rather override the way Django validates ImageFields. What I want to do is check if the passed value is a 64-bit string, if it is, modify it to a file type, then validate the ImageField. The below code works as is, I just don't feel is optimal.
Here is my view:
class UserCredentialList(generics.ListCreateAPIView):
permission_classes = (IsCredentialOwnerOrAdmin,)
serializer_class = CredentialSerializer
"""
This view should return a list of all the purchases
for the currently authenticated user.
"""
def get_queryset(self):
"""
This view should return a list of all models by
the maker passed in the URL
"""
user = self.request.user
return Credential.objects.filter(member=user)
def perform_create(self, serializer):
serializer.save(member_id=self.request.user.id)
def perform_authentication(self, request):
if request.method == 'POST':
data = request.data.pop('document_image', None)
from django.core.files.base import ContentFile
import base64
import six
import uuid
# Check if this is a base64 string
if isinstance(data, six.string_types):
# Check if the base64 string is in the "data:" format
if 'data:' in data and ';base64,' in data:
# Break out the header from the base64 content
header, data = data.split(';base64,')
# Try to decode the file. Return validation error if it fails.
try:
decoded_file = base64.b64decode(data)
except TypeError:
self.fail('invalid_image')
# Generate file name:
file_name = str(uuid.uuid4())[:12] # 12 characters are more than enough.
# Get the file name extension:
import imghdr
file_extension = imghdr.what(file_name, decoded_file)
file_extension = "jpg" if file_extension == "jpeg" else file_extension
complete_file_name = "%s.%s" % (file_name, file_extension,)
data = ContentFile(decoded_file, name=complete_file_name)
request.data['document_image'] = data
request.user
And here is my serializer:
class CredentialSerializer(serializers.ModelSerializer):
class Meta:
model = Credential
fields = (
'id',
'credential_type',
'credential_number',
'date_received',
'is_verified',
'date_verified',
'document_image',
)
And here is my model:
class Credential(models.Model):
"""Used to store various credentials for member validation."""
document_image = models.ImageField(
upload_to=get_upload_path(instance="instance",
filename="filename.ext",
path='images/credentials/'))
PASSENGER = 'P'
OWNER = 'O'
CAPTAIN = 'C'
CREDENTIAL_CHOICES = (
(PASSENGER, 'Passenger'),
(OWNER, 'Owner'),
(CAPTAIN, 'Captain'),
)
credential_type = models.CharField(max_length=1,
choices=CREDENTIAL_CHOICES,
default=PASSENGER)
credential_number = models.CharField(max_length=255)
date_received = models.DateTimeField(auto_now_add=True)
is_verified = models.BooleanField(default=False)
date_verified = models.DateTimeField(blank=True, null=True)
member = models.ForeignKey(settings.AUTH_USER_MODEL,
related_name='credentials')
I used the below link to help me, now I just want to figure out how override the proper method
Django REST Framework upload image: "The submitted data was not a file"
Well I've made one change since making: I have moved this function to my serializer and instead I now override the method: is_valid and that works as well. At least it's not in my view anymore.
So I have SQLite database using Slick and I want to add and remove tables from it.
Here is what I have now:
Here is the database element class:
class Data(tag: Tag)
extends Table[(Int, String)](tag, "myDB") {
// This is the primary key column:
def id = column[Int]("ID", O.PrimaryKey)
def name = column[String]("NAME")
// Every table needs a * projection with the same type as the table's type parameter
def * : ProvenShape[(Int, String)] = (id, name)
}
I need to be able to create multiple tables using the class above. Something like this:
def addTable(name:String){
db withSession { implicit session =>
val newTable = TableQuery[Data]
newTable.ddl.create
}
}
Problem is that I cant create new table because one already exists with name "myDB". I tried to add a parameter for the name of the Table in the class Data like so:
class Data(tag: Tag,tableName:String)
But then I couldn't create a table at all and got an error
unspecified value parameter tableName
And how can I query a specific table from the database given the table name?
I tried to Implement this using Map with table name pointing to a table, but it doesnt work because the Map is not saved anywhere and is reset everytime the program starts.
This is what I had for querying a table:
def getDataFromTable(tableName:String)
{
var res = ""
db withSession { implicit session =>
tables(tableName) foreach{
case (id,name)=>
res += id + " " + name + " "
}
}
res
}
Any help is appreciated!
Thanks!
Definition
class Data(tag: Tag, tableName: String)
extends Table[(Int, String)](tag, tableName){
...
Usage
(new TableQuery(Data(_,"table_1"))).ddl.create
(new TableQuery(Data(_,"table_2"))).ddl.create
...
I have a StructuredProperty that looks like this:
userDB(key=Key('userDB', 5580090230439936), name=u'Super User', orgs=[providers(name=u'Comp, Inc.', password=u'1111111', url=None, username=u'111111', value=u'comp'), providers(name=u'Systems, Inc.', password=u'2222222', url=None, username=u'222222', value=u'system')], update=None, userID=u'super#example.com')
I would like to delete every provider who's 'value' == 'system'.
class providers(EndpointsModel):
name = ndb.StringProperty()
value = ndb.StringProperty()
url = ndb.StringProperty()
username = ndb.StringProperty()
password = ndb.StringProperty()
class userDB(EndpointsModel):
userID = ndb.StringProperty(required=True, indexed=True)
name = ndb.StringProperty(required=True, indexed=True)
update = ndb.DateTimeProperty(auto_now_add=True, indexed=True)
orgs = ndb.StructuredProperty(providers, repeated=True, indexed=True)
system = ndb.StructuredProperty(system, repeated=True, indexed=True)
comp = ndb.StructuredProperty(comp, repeated=True, indexed=True)
I tried this:
def delOrgs(key, X): #Key is a userDB key and X is a list ['system']
for B in X:
for A in key[0].get().orgs:
del_provider = key[0].get().query(A.value == B).fetch(keys_only=True)
#del_provider[0].delete()
logging.info(del_provider)
but i get the following error:
TypeError: Cannot filter a non-Node argument; received False
Any help would be greatly appreciated.
Your query should look like:
userDB.query(userDB.orgs.value == 'system)
This will return all of the userDBs which have a provider with value == 'system'.
You'll then need to update the 'orgs' property of each, removing any that you don't want, and then re-put the entities:
users = query.fetch()
for user in users:
user.orgs = filter(lambda provider: provider.value != 'system', user.orgs)
ndb.put_multi(users)
Structured properties don't (or shouldn't) exist as independent entities, so you can't fetch them independently of the entity that contains them, and can't delete them directly.
I have 2 models:
Category(models.Model):
name = models.CharField(max_length=30)
no_of_posts = models.IntegerField(default=0) # a denormalised field to store post count
Post(models.Model):
category = models.ForeignKey(Category)
title = models.CharField(max_length=100)
desc = models.TextField()
user = models.ForeignKey(User)
pub_date = models.DateTimeField(null=True, blank=True)
first_save = models.BooleanField()
Since I always want to show the no. of posts alongwith each category, I always count & store them every time a user creates or deletes a post this way:
## inside Post model ##
def save(self):
if not pub_date and first_save:
pub_date = datetime.datetime.now()
# counting & saving category posts when a post is 1st published
category = self.category
super(Post, self).save()
category.no_of_posts = Post.objects.filter(category=category).count()
category.save()
def delete(self):
category = self.category
super(Post, self).delete()
category.no_of_posts = Post.objects.filter(category=category).count()
category.save()
........
My question is whether, instead of counting every object, can we not use something like:
category.no_of_posts += 1 // in save() # and
category.no_of_posts -= 1 // in delete()
Or is there a better solution!
Oh, I missed that! I updated the post model to include the relationship!
Yes, a much better solution:
from django.db.models import Count
class CategoryManager(models.Manager):
def get_query_set(self, *args, **kwargs):
qs = super(CategoryManager, self).get_query_set(*args, **kwargs)
return qs.annotate(no_of_posts=Count('post'))
class Category(models.Model):
...
objects = CategoryManager()
Since you didn't show the relationship between Post and Category, I guessed on the Count('posts') part. You might have to fiddle with that.
Oh, and you'll want to get rid of the no_of_posts field from the model. It's not necessary with this. Or, you can just change the name of the annotation.
You'll still be able to get the post count with category.no_of_posts but you're making the database do the legwork for you.