django model validation

Preface: This article is published in the form of learning records, the previous period of time suffering from the model aggregation in the group by find a long, the official article is not very clear to say group by, but in the document is mentioned!!!Model Improvement Section :Aggregation :LOrder.objects.values (' Com_chnl_name '). Annotate (Count (' serv_id '))#相当于select count (serv_id) from Lorder GROUP

Make a copy today, copy and modify some of the data, and then submit the form to a new instance.As a result, Google came out of the wrong, are the copy of each other code, probably as follows:1 obj = MyModel.objects.get (id=1)2 obj.pk = None3 obj.save ()Then finally found a correct, hereby record: 1 if Request.method = " post " 2 form = authorcopyform (Request. Post,instance=author) 3 if Form.is_valid (): 4 New_ Author = form.save (Commit=false) 5 new_a uthor.pk = None 6 new_aut

... Start ignoring case __endswith to ... End __iendswith with ... End, ignoring case __range in ... The __year date field in the Year __month date field of the month __day the date field of the Day __isnull=true/falseQ and F QueryFrom django.db.models import F, QQ for complex queriesAnd-XX.objects.filter (Q (f=1), Q (f=2)) # f = = 1 and F = = 2or and XX.objects.filter (q (f=1) | Q (f=2)) # f ==1 | f = = 2not-XX.objects.filter (~q (f=1), Q (f=2)) # f! = 1 and F = = 2　　F the val

First, create a single tablemodels.py#!/usr/bin/envpython#-*-coding:utf-8-*-from__future__importunicode_ Literalsfromdjango.dbimportmodelsclassuserinfo (models. Model):user_type_list= ( (1, "F"), (2, "M"),) Name=models. Charfield (max_length=32,primary_key=true) user_type=models. Integerfield (choices=user_type_list,default=1) ctime=models. Datetimefield (auto_now=true) uptime=models. Datetimefield (auto_now_add=true) email=models. Emailfield (max_le

Class talk (models. Model ):Time = models. datetimefield ()Content = models. textfield () After the above model is defined, the information generated by the table cannot be viewed using manage. py syncdb. Of course, the generated table is not seen in the MySQL database. Later I found that it was a problem with textfield. MySQL needed special settings to use this field. Later I saw the following in the

Python Learning -- Django -- connect to mysql to create a model 1. Create a project 2. Create the first page 3. Create an app 4. Add a page to the app 4.1 Configure in setting: Add Add Create views Then You can access it through 127.0.0.1: 8000. 5. Configure Database Modify database information in setting Check whether the database is connected In my workbench, we can see that the default table is

, the associated data is deleted, the value associated with it is set to the default value (if the FK field needs to be set default)-models. Set, delete the associated data, a. The value associated with it is set to the specified value, set: Models. Set (value) B. The value associated with it is set to the return value of the executable object, set: Models. SET (Executable object) def func (): Return class MyModel (models. Model): User = models. Forei

are mutually exclusive. any combination between them will result in an error.NoteIn the current implementation, setting Auto_now or auto_now_add to True will allow this field to get both editable=false and blank=true These two settings.NoteAuto_now and auto_now_add These two settings will always use the date of the default timezone (time zone) at the time the object is created or updated. If you don't want to do this, you can consider simply using your own default call or rewriting Save () to

The django model creates a new object and obtains an object. You can create an object using the following methods: Person. objects. create (name = name, age = age) P = Person (name = "WZ", age = 23)P. save () P = Person (name = "TWZ ")P. age = 23P. save () Person. objects. get_or_create (name = "WZT", age = 23)This method is a good way to prevent repeated operations, but the speed is relatively slow. A

The thing is this, I have a table for storing exams Class Exam (models. Model): category = Cached_fields. Foreignkeyfield (Category) name = models. Charfield (max_length=128) date = models. Datefield () created_at = models. Datetimefield (auto_now_add=true) updated_at = models. Datetimefield (auto_now=true) class Meta: Unique_together = (' category ', ' Date ') Category represents the type of examination, date indicates the day

you need to select the object from the collectionperson = Person_Tbl.objects.get (name=name)Person.delete ()Note: When using GET, a Person_tbl object is returned.person = Person_Tbl.objects.filter (name=name). Delete ()Iv. modifying an Object(1) Gets the object, then modifies, and finally save ()person = Person_Tbl.objects.filter (name=name)Cur_person = person[0]Cur_person.name = NameCur_person.height = 170Cur_person.save ()person = Person_Tbl.objects.get (name=name)Person.name = NamePerson.hei

Default Value of Django model. py form can be blank by default, djangomodel. py Field. null The default value is null = False. In this case, NULL data cannot be input, but it can be a null character. If BooleanField wants a null data type, you can select NullBooleanField Field. blank The default value is blank = False, indicating that the default value is not allowed to be blank. If blank = True, the

This is the case. I have a table that stores the exam.Class Exam (models. Model ):Category = cached_fields.ForeignKeyField (Category)Name = models. CharField (max_length = 128)Date = models. DateField ()Created_at = models. DateTimeField (auto_now_add = True)Updated_at = models. DateTimeField (auto_now = True)Class Meta:Unique_together = ('Category ', 'date ')Category indicates the examination type, and date indicates the examination d