django --- orm --- --- summary of "one to one" --- "one to many" --- "many to many" --- "CRUD"

Single table CRUD

----- increase in 2 ways

method one:

models.Teacher.objects.create (tname = "Li")

Method Two:

obj = models.Teacher (tname = "Wang")
obj.save ()

----- Inquire

1, get all values

obj = models.Teacher.objects.all()

print(obj)

<QuerySet [<Teacher: Zhang>, <Teacher: Zhang>, <Teacher: Li>, <Teacher: Wang>]>

2, get the first value

obj = models.Teacher.objects.first()

print(obj)

Teacher Zhang

3, to obtain a final value

obj = models.Teacher.objects.last()

print(obj)

Teacher Wong

 

4, any one query

obj = models.Teacher.objects.filter(id=3)

print(obj)

<QuerySet [<Teacher: Li>]>

5, the query id is greater than 2 teacher

obj = models.Teacher.objects.filter(id__gt=2)

print(obj)

<QuerySet [<Teacher: Li>, <Teacher: Wang>]>

6, query id is greater than the first teacher 2

obj = models.Teacher.objects.filter(id__gt=2).first()

print(obj)

Teacher Li

----- modification

models.Teacher.objects.filter(id=3).update(tname="wangsi")

----- delete

models.Teacher.objects.filter(id=3).delete()

 

view.py

from django.shortcuts Import the render, HttpResponse, redirect
 from ormapp   Import Models
 DEF index (Request):
     # increased by 2 methods 
    # models.Teacher.objects.create (tname = "Li") 

    # obj = models.Teacher (tname = "Wang") 
    # obj.save () 

    # inquiry 
    # obj = models.Teacher.objects.all () Gets all 
    # obj = models.Teacher.objects.first () Gets the first 
    # obj = models.Teacher. objects.last () Gets the last 
    # obj = models.Teacher.objects.filter (id =. 3) at any of a query 
    # obj = models.Teacher.objects.filter (id__gt = 2) is greater than 2 teacher query id 
    #The first teacher obj = models.Teacher.objects.filter (id__gt = 2) .first () query id is greater than 2 
    models.Teacher.objects.filter (id =. 3) .Update (tname = " wangsi " ) 
    Models. Teacher.objects.filter (the above mentioned id = 3 ) .Delete ()
     return HttpResponse ( " filling success " )

models.py

from django.db import models

class Teacher(models.Model):
    tname = models.CharField(max_length=32)

    def __str__(self):
        return self.tname


class Classes(models.Model):
    title = models.CharField(max_length=32)
    ct = models.ManyToManyField("Teacher")

    def __str__(self):
        return self.name

class student(models.Model):
    name = models.CharField(max_length=32)
    age Models.BooleanField = (default = ' M ' ) 
    SC = models.ForeignKey (the Classes, on_delete = True) 

    "" " Display information defining each data object " "" 
    DEF  __str__ (Self):
         return the self.name

urls.py

"""
from django.contrib import admin
from django.urls import path
from ormapp import views

urlpatterns = [
    path('index/', views.index),
]

 

Table change search many additions

Table-many CRUD