Django Database basic Operations-Delete and change (tip)-Basic

1. Inserting data

1 Python code2>>> fromBooks.modelsImportPublisher3>>> P1 = Publisher (name='Apress', address='2855 Telegraph Avenue',  4... city='Berkeley', state_province='CA', country='U.S.A.',  5... website='http://www.apress.com/')  6>>> P1.save ()

1>>> fromBooks.modelsImportPublisher2>>> P1 = Publisher (name='Apress', address='2855 Telegraph Avenue',  3... city='Berkeley', state_province='CA', country='U.S.A.',  4... website='http://www.apress.com/')  5>>> P1.save ()

2. Enquiry

1 Python code 2 >>> Publisher.objects.all ()  3 [<publisher:apress>, <publisher:o ' Reilly>]  

1 [python] view plain copy 2 >>> Publisher.objects.all ()  3 [<publisher:apress>, < Publisher:o'reilly>]  

To get a single object:

1 Python code 2 >>> Publisher.objects.get (name="Apress")  3 <Publisher:Apress>  

1 [python] view plain copy 2 >>> Publisher.objects.get (name="Apress")   3 <Publisher:Apress>  

Throws an exception if the result is multiple objects or no results are returned

3. Conditions

Screening:

1 Python code 2 >>> Publisher.objects.filter (name='Apress')  3 

1 >>> Publisher.objects.filter (name='Apress')   2 [<publisher:apress>]  

1 Python code 2 >>> Publisher.objects.filter (name__contains="Press")   3 [<publisher:apress>]  

1 [python] view plain copy 2 >>> Publisher.objects.filter (name__contains="Press")   3

The __contains part will be translated into a like statement by Django

Sort:

1 Python code 2 >>> Publisher.objects.order_by ("name")  3 [<publisher:apress>, <publisher:o'reilly>

1 python] View plain copy2 >>> Publisher.objects.order_by ("name"  )  3 [<publisher:apress>, <publisher:o'reilly>]  

Equivalent to ORDER by name ASC

1 Python code 2 >>> Publisher.objects.order_by ("-name")  

1 [python] view plain copy 2 >>> Publisher.objects.order_by ("-name"

Add a minus sign equivalent to order BY name Desc

To limit the return data:

1 Python code 2 >>> Publisher.objects.order_by ('name') [0]   3 <Publisher:Apress>  

1 [python] view plain copy 2 >>> Publisher.objects.order_by ('name') [0]  3 <Publisher:Apress>

Equivalent to limit 1

1 Python code 2 >>> Publisher.objects.order_by ('name') [0:2]  

1 [python] view plain copy 2 >>> Publisher.objects.order_by ('name') [0:2]  

Equivalent to OFFSET 0 LIMIT 2

4. Update

1 Python code 2 >>> Publisher.objects.filter (id=52). Update (name='Apress publishing  ')  

1 [python] view plain copy 2 >>> Publisher.objects.filter (id=52). Update (name='Apress publishing' )  

 1  python code  2  >>> p = Publisher.objects.get (Name= "  apress   ")  #   first query  3  >>> p.name =  " apress Publishing   " #   update  4  >>> p.save () #   save  

1 [python] view plain copy 2 >>> p = Publisher.objects.get (name='Apress'# First Query   3'Apress publishing'# update   4 >>> p.save ()  # Save  

5. Delete

1 Python code 2 >>> p = Publisher.objects.get (name="O ' Reilly")  3 >>> P.delete ()  

1 [python] view plain copy 2 >>> p = Publisher.objects.get (name="O ' Reilly")   3 >>> p.delete ()  

1 Python code 2 >>> Publisher.objects.filter (country='USA'

1 [python] view plain copy 2 >>> Publisher.objects.filter (country='USA'). Delete ()  

Django Database basic Operations-Delete and change (tip)-Basic