Django learning - model and database operation (II)

1、mysql as well as mysql-workbench install （MAC-OS）

• mysql download
  • Download address , Click here ！！
• mysql-workbench download
  • Download address , Click here ！！

2、Django Database operation

• To configure Django To link a database mysql
  
• Configure Links mysql Database information
  
• Use mysql-bench newly build Database name by ：byte
  
• stay testdj In the project newly build app（TestModels）, As shown in the figure ：
• newly build app The order is as follows ：

django-admin startapp TestModel

• stay setting.py in To configure TestModels, This can be done in testdj Direct drinking under the directory testModel Module content
  
• stay TestModel/models.py Write the database model in
  
• stay terminal Execute the following commands in ：

$ python manage.py migrate   #  Create a table structure 

$ python manage.py makemigrations TestModel  #  Give Way  Django  Know we have some changes in our model 
$ python manage.py migrate TestModel   #  Create a table structure 

• If successful , stay mysql As shown in the following figure
  
• Add operation
  

 # 1、 Add operation 
    test1 = Test(name='byte')
    test1.save()
    # return HttpResponse("<p> Data added successfully ！</p>")

• Query operation
  

    # 2、 Query operation 
    response = ""
    response1 = ""
    #  adopt objects Of the model manager all() Get all the data lines , amount to SQL Medium SELECT * FROM
    list = Test.objects.all()
    # filter amount to SQL Medium WHERE, Conditions can be set to filter results 
    response2 = Test.objects.filter(id=5)
    #  Get single object 
    response3 = Test.objects.get(id=5)
    #  Limit data returned   amount to  SQL  Medium  OFFSET 0 LIMIT 2;
    list1 = Test.objects.order_by('name')[0:2]
    #  Data sorting 
    # Test.objects.order_by("id")
    # #  The above method can be used in chain 
    # Test.objects.filter(name="byte").order_by("id")
    #  Output all data 
    for var in list1:
        response1 += var.name + " "
    response = response1

• update operation
  

    # # 3. Update modification operation 
    # test1 = Test.objects.get(id=1)
    # test1.name = 'byte-Google-1'
    # test1.save()

    #  Another way 
    # Test.objects.filter(id=1).update(name='Google')

    #  Modify all columns 
    # Test.objects.all().update(name='Google')

• Delete operation
  

   # 4. Delete operation 
    #  Delete id=1 The data of 
    # test1 = Test.objects.pop(id)
    # test1.delete()

    #  Another way 
    # Test.objects.filter(id=1).delete()

    #  Delete all data 
    # Test.objects.all().delete()