Django Database basic operations-additions and deletions (tip)-Basic __ Database

Original address

1. Inserting data

Python code >>> from books.models import publisher >>> P1 = publisher (name= ' Apress ', address= ' 2855 Telegr    APh Avenue ', ... city= ' Berkeley ', state_province= ' CA ', country= ' U.S.A ', ... website= ' http://www.apress.com/') >>> P1.save () >>> from books.models import publisher >>> P1 = Publisher (name= ' Apress ', add ress= ' 2855 Telegraph Avenue ', ... city= ' Berkeley ', state_province= ' CA ', country= ' U.S.A ', ... website= ' http:// www.apress.com/') >>> P1.save ()

2, inquiry

Python code >>> Publisher.objects.all () [<publisher:apress>, <publisher:o ' reilly>] >>> Pu Blisher.objects.all () [<publisher:apress>, <publisher:o ' reilly>]

To get a single object:

Python code >>> Publisher.objects.get (name= "Apress") <Publisher:Apress> >>> Publisher.objects.get (name= "Apress") <Publisher:Apress> throws an exception if the result is multiple objects or no results are returned

3, Conditions

Screening:

Python code >>> Publisher.objects.filter (name= ' Apress ') [<publisher:apress>] >>> Publisher.objects.filter (name= ' Apress ') [<publisher:apress>]
Python code >>> Publisher.objects.filter (name__contains= "Press") [<publisher:apress>] >>> Publisher.objects.filter (name__contains= "Press") [<publisher:apress>] __contains part is translated into like statements by Django

Sort:

Python Code >>> Publisher.objects.order_by ("name") [<publisher:apress>, <publisher:o ' reilly>] ;>> Publisher.objects.order_by ("name") [<publisher:apress>, <publisher:o ' reilly>]

Equivalent to ORDER by name ASC

Python Code >>> Publisher.objects.order_by ("-name") >>> Publisher.objects.order_by ("-name") plus a minus sign equals ORDER BY name Desc

Limit return Data:

Python code >>> Publisher.objects.order_by (' name ') [0] <Publisher:Apress> >>> publisher.objects . order_by (' name ') [0] <Publisher:Apress> equivalent limit 1

Python code >>> Publisher.objects.order_by (' name ') [0:2] >>> Publisher.objects.order_by (' name ') [0:2] Equivalent to OFFSET 0 LIMIT 2

4, update

Python code >>> Publisher.objects.filter (id=52). Update (name= ' Apress Publishing ') >>> Publisher.objects.filter (id=52). Update (name= ' Apress Publishing ')
Python code >>> p = Publisher.objects.get (name= ' Apress ') #先查询 >>> p.name = ' Apress Publishing ' #更新 > >> p.save () #保存 >>> p = Publisher.objects.get (name= ' Apress ') #先查询 >>> p.name = ' Apress Publishi Ng ' #更新 >>> p.save () #保存
5, delete

Python code >>> p = Publisher.objects.get (name= "O ' Reilly") >>> p.delete () >>> p = Publisher.ob Jects.get (name= "O ' Reilly") >>> P.delete ()
Python code >>> Publisher.objects.filter (country= ' USA '). Delete () >>> Publisher.objects.filter ( country= ' USA '). Delete ()