Model (operation table) and djangomodel operation table in Django

Model (operation table) and djangomodel operation table in Django
Model operation table

 

I. Basic operations

1 # Add 2 3 models. tb1.objects. create (c1 = 'XX', c2 = 'oo ') # Add a data record and accept Dictionary data ** kwargs 4 5 obj = models. tb1 (c1 = 'XX', c2 = 'oo ') 6 obj. save () 7
Dic = {'c1 ': 'XX', 'c2': 'oo '}
Models. Tb1.objects. create (** dic) # The output result of Form is a dictionary. You can create data directly in the database based on the dictionary of this Form and **.

8 # query 9 10 models. tb1.objects. get (id = 123) # get a single piece of data. If no data exists, an error is returned (not recommended) 11 models. tb1.objects. all () # Get all. first () Fetch the first data 12 models. tb1.objects. filter (name = 'seven') # You can use the ** method to obtain the data of a specified condition to pass the parameter 13 14 # Delete 15 16 models. tb1.objects. filter (name = 'seven '). delete () # delete the data of the specified condition 17 18 # Change 19 20 models. tb1.objects. filter (name = 'seven '). update (gender = '0') # update the data of the specified condition. ** kwargs21 22 obj = models is supported. tb1.objects. get (id = 1) 23 obj. c1 = '000000' 24 obj. save () # modify a single data record

 

Take a closer look at the data types retrieved from the database:

1 w = models.Simp.objects.all()2 print w, type(w)
3 [<Simp: chenc>, <Simp: zan>, <Simp: zhangsan>]    <class 'django.db.models.query.QuerySet'>

 

 As you can see, retrieving data from the database looks like a list of contained objects. In fact, the whole data is a special type in django.QuerySet.

. All ()Is to obtain data of all columns, you can add. Values ()Extracts a column, and the value of each item isDictionary:

1 w = models.Simp.objects.all().values('username')2 print w, type(w)

[{'username': u'chenc'}, {'username': u'zan'}, {'username': u'zhangsan'}] <class 'django.db.models.query.QuerySet'>

. Values_list (),The obtained value isTuples

1 w = models.Simp.objects.all().values_list('username')2 print w, type(w)

[(u'chenc',), (u'zan',), (u'zhangsan',)] <class 'django.db.models.query.QuerySet'>

. Values_list ()You can also add multiple parameters: (you can use Form to generate a dynamic select statement on the front-end)

1 w = models.Simp.objects.all().values_list('id', 'username')2 print w, type(w)

[(1, u'chenc'), (2, u'zan'), (3, u'zhangsan')] <class 'django.db.models.query.QuerySet'>

 

QueryYou can view the executed SQL statement:

1 b = models.Simp.objects.all()2 print b.query

SELECT "app01_simp"."id", "app01_simp"."username", "app01_simp"."password" FROM "app01_simp"

 

 

II,