I'm using django to create database tables,model code like this:
class User(models.Model):
uid = models.CharField(max_length=32,primary_key=True)
nick = models.CharField(max_length=20)
sex = models.CharField(max_length=1,default='M')
sign = models.CharField(max_length=40,default="")
but default value doesn't work.when I show table description,shows that:
why this code doesn't work and how can solve this problem?
Django doesn't add default values into the schema, instead it adds the default value if need-be when a User object is created.
Related
I have made a field facility_id in Django models that should concatenate a specific string "ACCTS-" on the left with each record's id on the right,
My model class is below:
class Facility(models.Model):
...
id = models.BigAutoField(primary_key=True)
facility_id = models.CharField(max_length=50, default=print(f'{"ACCTS-"}{id}'), editable=False)
...
I want to the facility_id field to be storing special and readable human friendly facility_id's of the form: ACCTS-1, ACCTS-2, ACCTS-3, ... corresponding to each individual id.
The migrations didn't throw any errors, however When I try to create the records for this table in the Django Admin, am getting an IntegrityError of:
IntegrityError at /admin/ACCTS_CLYCAS/facility/add/
NOT NULL constraint failed: ACCTS_CLYCAS_facility.facility_id
How do I fix this problem, or what could be the easiest way to implement my problem.
The migrations didn't throw any errors, however When I try to create the records for this table in the Django Admin
That makes sense, since you have set the default=None. Indeed, print(…) returns None and only prints the value to the standard output channel (stdout). It will thus not prepend the value of the id with ACCTS.
If the facility_ids are all just the id prefixed with ACCTS-, you can work with a #property instead:
class Facility(models.Model):
id = models.BigAutoField(primary_key=True)
#property
def facility_id(self):
return f'ACCTS-{self.id}'
You can also try using a post save signal.
Add blank = True to facility_id and then use a post save signal to update the value of facility_id.
You can watch this tutorial on how to use Django Signals
When i use a long name in db_columns at a field in Models.py, django does not work correct. It truncates the name, and add random letters/numbers at the end.
Like this: db_column='my_loooooooooooooooooong_column_name'
And when i try queryset, django returns:
'table name'.'my_looooooooooooooo6E4': invalid identifier.
My scenario in detail:
I have a legacy database in Oracle.
The table name in database: PALAVRA_CHAVE_ENTREGA_VALOR
With 3 Fields: PCEV_CD_PALAVRA_CHAVE_ENTREGA_VALOR (Primary Key), PACH_CD_PALAVRA_CHAVE, ENVA_CD_ENTREGA_VALOR
In my models.py:
class PalavraChaveEntregaValor(models.Model):
pcev_cd_palavra_chave_entrega_valor = models.BigIntegerField(primary_key=True, db_column='pcev_cd_palavra_chave_entrega_valor')
pach_cd_palavra_chave = models.BigIntegerField()
enva_cd_entrega_valor = models.BigIntegerField()
class Meta:
managed = False
db_table = 'palavra_chave_entrega_valor'
When i run in shell (python manage.py shell) this command:
PalavraChaveEntregaValor.objects.all()
I got output: DatabaseError: ORA-00904: "PALAVRA_CHAVE_ENTREGA_VALOR"."PCEV_CD_PALAVRA_CHAVE_ENTRA6E4": invalid identifier
I made a test, changed the long name PCEV_CD_PALAVRA_CHAVE_ENTREGA_VALOR to PCEV_CD, and everthing works fine..
Is there a limitation of characters in db_columns at django? Is there a workaround for this? If not, i will have to create a lot of Views in Oracle Database with shorter names of columns only for django work.. Change the current table column names is not an option.
I created a many2one field that has relationship custom model. I want to know how to self default value. My default value is "Head/Branch".
Here is my code. Thank You.
from odoo import models, fields, api
import logging
class CrmnNewTask(models.Model):
_inherit = 'res.partner'
head_branch=fields.Many2one('head.branch', string='Head/Branch',index=True, ondelete='cascade')
class Headbranch(models.Model):
_name='head.branch'
name=fields.Char('Head/Branch')
Please implement this example in your code :
user_id = fields.Many2one('res.users','User', default=lambda self: self.env.user)
Here I have set current user name in many2one field. You can also set default value using function. This one another example :
*
tax_group_id = fields.Many2one('account.tax.group', string="Tax Group", default=_default_tax_group, required=True)
#api.model
def _default_tax_group(self):
return self.env['account.tax.group'].search([], limit=1)
*
Try this:
Go to your form where is field head_branch
Active developer mode
Populate field and save as default https://imgur.com/a/fQd03
I'm using Flask with the Peewee ORM in which I have defined two tables like so:
class Ticket(db.Model):
created = DateTimeField(default=datetime.now)
customer_uuid = CharField() # the customer's UUID gotten from App. More info comes from bunq API.
ticket_type = ForeignKeyField(TicketType, related_name='tickets')
active = BooleanField(default=True)
class Assign(db.Model):
created = DateTimeField(default=datetime.now)
ticket = ForeignKeyField(Ticket, related_name='assigned_to')
user = ForeignKeyField(User, related_name='assigned_tickets')
In the Assign table, several users can be assigned to a ticket, but only the last one counts (i.e., if a new user gets assigned, the previous ones should be disregarded). So I select the active tickets using the following:
open_tickets = Ticket.select().where(Ticket.active == True)
I now want to use this loop in my template. With every iteration however, I also want to display the assigned user. But open_ticket[0].assigned_to obviously returns several assignments, and with it several users.
Would anybody know how I can get the latest assigned user for every ticket within a loop?
This worked for me in Sqlite:
q = (Ticket
.select(Ticket, Assign, User)
.join(Assign)
.join(User)
.group_by(Ticket)
.order_by(Ticket.id, Assign.id.desc()))
for ticket in q:
print ticket.id, ticket.assign.user.username
Basically what Im trying to make is a data structure where it has the users name, id, and datejoined. Then i want a "sub-structure" where it has the users "text" and the date it was modified. and the user will have multiple instances of this text.
class User(db.Model):
ID = db.IntegerProperty()
name = db.StringProperty()
datejoined = db.DateTimeProperty(auto_now_add=True)
class Content(db.Model):
text = db.StringProperty()
datemod= db.DateTimeProperty(auto_now_add = True)
Is the code set up correctly?
One problem you will have is that making User.ID unique will be non-trivial. The problem is that two writes to the database could occur on different shards, both check at about the same time for existing entries that match the uniqueness constraint and find none, then both create identical entries (with regard to the unique property) and then you have an invalid database state. To solve this, appengine provides a means of ensuring that certain datastore entities are always placed on the same physical machine.
To do this, you make use of the entity keys to tell google how to organize the entities. Lets assume you want the username to be unique. Change User to look like this:
class User(db.Model):
datejoined = db.DateTimeProperty(auto_now_add=True)
Yes, that's really it. There's no username since that's going to be used in the key, so it doesn't need to appear separately. If you like, you can do this...
class User(db.Model):
datejoined = db.DateTimeProperty(auto_now_add=True)
#property
def name(self):
return self.key().name()
To create an instance of a User, you now need to do something a little different, you need to specify a key_name in the init method.
someuser = User(key_name='john_doe')
...
someuser.save()
Well, really you want to make sure that users don't overwrite each other, so you need to wrap the user creation in a transaction. First define a function that does the neccesary check:
def create_user(username):
checkeduser = User.get_by_key_name(username)
if checkeduser is not None:
raise db.Rollback, 'User already exists!'
newuser = User(key_name=username)
# more code
newuser.put()
Then, invoke it in this way
db.run_in_transaction(create_user, 'john_doe')
To find a user, you just do this:
someuser = User.get_by_key_name('john_doe')
Next, you need some way to associate the content to its user, and visa versa. One solution is to put the content into the same entity group as the user by declaring the user as a parent of the content. To do this, you don't need to change the content at all, but you create it a little differently (much like you did with User):
somecontent = Content(parent=User.get_by_key_name('john_doe'))
So, given a content item, you can look up the user by examining its key:
someuser = User.get(somecontent.key().parent())
Going in reverse, looking up all of the content for a particular user is only a little trickier.
allcontent = Content.gql('where ancestor is :user', user=someuser).fetch(10)
Yes, and if you need more documentation, you can check here for database types and here for more info about your model classes.
An alternative solution you may see is using referenceproperty.
class User(db.Model):
name = db.StringProperty()
datejoined = db.DateTimeProperty(auto_now_add=True)
class Content(db.Model):
user = db.ReferenceProperty(User,collection_name='matched_content')
text = db.StringProperty()
datemod= db.DateTimeProperty(auto_now_add = True)
content = db.get(content_key)
user_name = content.user.name
#looking up all of the content for a particular user
user_content = content.user.matched_content
#create new content for a user
new_content = Content(reference=content.user)