Django的form表单一般具有两种功能
1. 验证输入
2.输入HTML
---------模板----------- from django import forms class BookForm(forms.Form): name = forms.CharField(max_length=10) publish_date = forms.DateField() -------视图----------- def forms(request): Forms = form_models.BookForm() if request.method == 'POST': print(request.POST) Forms = form_models.BookForm(request.POST) if Forms.is_valid(): print("form is ok") form_data = Forms.cleaned_data print('form1---',form_data) form_data['publisher_id'] = request.POST.get('publisher_id') print('form2---',form_data) book_obj = models.Book(**form_data) book_obj.save() else: print(Forms.errors) publisher_list = models.Publisher.objects.all() return render(request,'formspage/forms.html',{'forms':Forms, "publishers":publisher_list}) --------------html------------ <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="" method="post">{% csrf_token %} {{ forms }} <select name="publisher_id"> {% for publisher in publishers %} <option value="{{ publisher.id }}">{{ publisher.name }}</option> {% endfor %} }} </select> <input type="submit" value="submit"> </form> </body> </html>
-----增加复杂度
#!/usr/bin/env python # -*- coding:utf-8 -*- import re from django import forms from django.core.exceptions import ValidationError def mobile_validate(value): mobile_re = re.compile(r'^(13[0-9]|15[012356789]|17[678]|18[0-9]|14[57])[0-9]{8}$') if not mobile_re.match(value): raise ValidationError('手机号码格式错误') class PublishForm(forms.Form): user_type_choice = ( (0, u'普通用户'), (1, u'高级用户'), ) user_type = forms.IntegerField(widget=forms.widgets.Select(choices=user_type_choice, attrs={'class': "form-control"})) title = forms.CharField(max_length=20, min_length=5, error_messages={'required': u'标题不能为空', 'min_length': u'标题最少为5个字符', 'max_length': u'标题最多为20个字符'}, widget=forms.TextInput(attrs={'class': "form-control", 'placeholder': u'标题5-20个字符'})) memo = forms.CharField(required=False, max_length=256, widget=forms.widgets.Textarea(attrs={'class': "form-control no-radius", 'placeholder': u'详细描述', 'rows': 3})) phone = forms.CharField(validators=[mobile_validate, ], error_messages={'required': u'手机不能为空'}, widget=forms.TextInput(attrs={'class': "form-control", 'placeholder': u'手机号码'})) email = forms.EmailField(required=False, error_messages={'required': u'邮箱不能为空','invalid': u'邮箱格式错误'}, widget=forms.TextInput(attrs={'class': "form-control", 'placeholder': u'邮箱'})) ''' def __init__(self, *args, **kwargs): super(SampleImportForm, self).__init__(*args, **kwargs) self.fields['idc'].widget.choices = models.IDC.objects.all().order_by('id').values_list('id','display') self.fields['business_unit'].widget.choices = models.BusinessUnit.objects.all().order_by('id').values_list('id','name') Forms ''' 先写好一个form
def test_form_view(request): if request.method == 'POST': request_form = PublishForm(request.POST) if request_form.is_valid(): request_dict = request_form.clean() print(request_dict) return render(request,'test.html', {'pub_form':request_form}) else: pub_form = PublishForm() return render(request,'test.html',{'pub_form':pub_form}) 写好视图
<div>
<form method="post" action="{% url 'test_form' %}">{% csrf_token %}
<div>{{ pub_form.user_type }} {{ pub_form.errors.title }}</div>
<div>{{ pub_form.title }}</div>
<div>{{ pub_form.email }}</div>
<div>{{ pub_form.phone }}</div>
<div>{{ pub_form.memo }}</div>
{% if pub_form.errors %}
{{ pub_form.errors }}
{% endif %}
<input type="submit" value="提交">
</form>
</div>
模版文件
扩展：ModelForm
在使用Model和Form时，都需要对字段进行定义并指定类型，通过ModelForm则可以省去From中字段的定义
class ModelForm(forms.ModelForm): class Meta: model = models.Book # fields = ('name','publish_date') #选择指定关联字段在前端显示 exclude = ()# 如果不指定选择显示的字段，必须指定exclude ，选择不显示的字段 空表示无 widgets = { 'name':forms.TextInput(attrs={'class':"form_control"}), # name字段加样式 }
def book_modelform(request): form = form_models.ModelForm() print(form) if request.method == "POST": print(request.POST) form = form_models.ModelForm(request.POST) if form.is_valid(): print("form is ok") form.save() print(form.errors) return render(request,'formspage/modelform.html',{"forms":form})
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> .form_control{ background-color: blue; } </style> </head> <body> <form action="" method="post">{% csrf_token %} <div> {% for ele in forms %} <div class="form-ele"> <label style="width: 100px ;float: left">{{ ele.name }}</label> <label>{{ ele }}{{ ele.errors }}</label> </div> {% endfor %} </div> <input type="submit" value="submit"> </form> </body> </html>
Django Admin定制
django amdin是django提供的一个后台管理页面，改管理页面提供完善的html和css，使得你在通过Model创建完数据库表之后，就可以对数据进行增删改查，而使用django admin 则需要以下步骤：
- 创建后台管理员
- 配置url
- 注册和配置django admin后台管理页面
1、创建后台管理员
python manage.py createsuperuser
2、配置后台管理url
url(r'^admin/', include(admin.site.urls))
3、注册和配置django admin后台页面
a、在admin中执行如下配置
from django.contrib import admin
from books import models
admin.site.register(models.UserType)
admin.site.register(models.UserInfo)
admin.site.register(models.UserGroup)
admin.site.register(models.Asset)
b、设置数据表名称
class Author(models.Model): name = models.CharField(max_length=50) email = models.EmailField() class Meta: verbose_name = '认证名字'#verbose_name的意思很简单，就是给你的模型类起一个更可读的名字 verbose_name_plural = '认证名字'#如果不指定Django会自动在模型名称后加一个’s’
c、定制自定义显示字段
rom django.contrib import admin class entry(admin.ModelAdmin): list_display = ('headline','body_text','pub_date','mod_date','n_comments','n_pingbacks')#自定义显示字段 # Register your models here. from blog import models admin.site.register(models.Blog) admin.site.register(models.Author) admin.site.register(models.Entry,entry)
d、添加页面搜索过滤等功能
#admin 定制功能 class BookAdmin(admin.ModelAdmin): list_display = ('id','name','publisher','publish_date','status','colored_status') #显示的字段信息，# 注： 不能显示多对多字段 search_fields = ('name','publisher__name',) #添加搜索框 list_filter = ('publisher','publish_date',) # 过滤功能 list_editable = ('name','publish_date',) # 前端可直接修改的字段 list_per_page = 10 #每页内容 filter_horizontal = ('authors',) # 针对多对多的水平筛选搜索 raw_id_fields = ('publisher',) #搜索外键 actions = [make_forbidden,] # d定制admin action # Register your models here. from books import models admin.site.register(models.Author) admin.site.register(models.Publisher) admin.site.register(models.Book,BookAdmin) #BookAdmin 是将自己写的类作为参数封装到注册admin
常用ORM操作
from django.db import models class Blog(models.Model): name = models.CharField(max_length=100) tagline = models.TextField() def __str__(self): # __unicode__ on Python 2 return self.name class Author(models.Model): name = models.CharField(max_length=50) email = models.EmailField() def __str__(self): # __unicode__ on Python 2 return self.name class Entry(models.Model): blog = models.ForeignKey(Blog) headline = models.CharField(max_length=255) body_text = models.TextField() pub_date = models.DateField() mod_date = models.DateField() authors = models.ManyToManyField(Author) n_comments = models.IntegerField() n_pingbacks = models.IntegerField() rating = models.IntegerField() def __str__(self): # __unicode__ on Python 2 return self.headline 示例models
个人示例代码
# 创建一个py脚本来来方便调试增删改查 import os from django.db.models import F,Q,Count,Sum,Avg,Min,Max os.environ['DJANGO_SETTINGS_MODULE']='day16.settings' #将setting模板加入环境变量 import django # 导入django django.setup() from blog import models # foreignkey关联 # entry = models.Entry.objects.get(pk=1) # 查询主键为1 # print(entry.blog) # blog = models.Blog.objects.get(id=2) # print(blog) # entry.blog = blog # entry.save() # manytomany关联 # NZ = models.Author.objects.create(name='小哪吒') # LH = models.Author.objects.create(name='老虎') # entry.authors.add(NZ,LH) # 单表内查询语句链式查询 #all_entries = Entry.objects.all() #查询所有 # Entry.objects.filter(pub_date__year=2006) #查询所有pub_date为2006年的纪录 # Entry.objects.all().filter(pub_date__year=2006) #与上面那句一样 # >>> Entry.objects.filter( #链式查询 # ... headline__startswith='What' # ... ).exclude( # ... pub_date__gte=datetime.date.today() # ... ).filter( # ... pub_date__gte=datetime(2005, 1, 30) # ... ) # # one_entry = Entry.objects.get(pk=1) #单条查询 # # Entry.objects.all()[:5] #查询前5条 # Entry.objects.all()[5:10] #查询第五条-第十条 # # Entry.objects.order_by('headline')[0] #按headline排序取第一条 #obj = models.Entry.objects.get(blog__name__contains='生活') 查找出blog字段中对应的外键Blog name=生活的板块 # Entry.objects.filter(pub_date__lte='2006-01-01') #相当于sql语句SELECT * FROM blog_entry WHERE pub_date <= '2006-01-01'; # # Entry.objects.get(headline__exact="Cat bites dog") #相当于SELECT ... WHERE headline = 'Cat bites dog'; # Blog.objects.get(name__iexact="beatles blog") #与上面相同,只是大小写不敏感 # # Entry.objects.get(headline__contains='Lennon') #相当 于SELECT ... WHERE headline LIKE '%Lennon%'; # # objs = models.Entry.objects.filter(n_comments__lte=F('n_pingbacks')) # print(objs) # addblog = models.Blog.objects.create(name='python') objs = models.Entry.objects.filter(Q(mod_date=('2016-05-21')) and Q(n_comments__lt=F('n_pingbacks')) | Q(pub_date__lt='2016-05-17')) print(objs) # print(models.Entry.objects.all().aggregate(Avg('n_pingbacks'), # Sum('n_pingbacks'), # Min('n_pingbacks') # )) # print('=============================') from books import models as book_models # pub_obj = book_models.Publisher.objects.first() # print(pub_obj.name,pub_obj.book_set.select_related())# 反向关联查询 #book_set是反向关联自动生成的一个字段 # print("=================================") pub_objs = book_models.Publisher.objects.annotate(book_nums=Count('book')) #分类聚合 for publisher in pub_objs: print(publisher.book_nums)
处理带外键关联或多对多关联的对象
>>> from blog.models import Entry >>> entry = Entry.objects.get(pk=1) >>> cheese_blog = Blog.objects.get(name="Cheddar Talk") >>> entry.blog = cheese_blog >>> entry.save()
ManyToManyField关联
NZ = models.Author.objects.create(name='小哪吒') LH = models.Author.objects.create(name='老虎') entry.authors.add(NZ,LH)
单表内查询语句链式查询
all_entries = Entry.objects.all() #查询所有 Entry.objects.filter(pub_date__year=2006) #查询所有pub_date为2006年的纪录 Entry.objects.all().filter(pub_date__year=2006) #与上面那句一样 >>> Entry.objects.filter( #链式查询 ... headline__startswith='What' ... ).exclude( ... pub_date__gte=datetime.date.today() ... ).filter( ... pub_date__gte=datetime(2005, 1, 30) ... ) one_entry = Entry.objects.get(pk=1) #单条查询 Entry.objects.all()[:5] #查询前5条 Entry.objects.all()[5:10] #查询第五条-第十条 Entry.objects.order_by('headline')[0] #按headline排序取第一条 obj = models.Entry.objects.get(blog__name__contains='生活') 查找出blog字段中对应的外键Blog name=生活的板块 Entry.objects.filter(pub_date__lte='2006-01-01') #相当于sql语句SELECT * FROM blog_entry WHERE pub_date <= '2006-01-01'; Entry.objects.get(headline__exact="Cat bites dog") #相当于SELECT ... WHERE headline = 'Cat bites dog'; Blog.objects.get(name__iexact="beatles blog") #与上面相同,只是大小写不敏感 Entry.objects.get(headline__contains='Lennon') #相当 于SELECT ... WHERE headline LIKE '%Lennon%';
关联查询
#This example retrieves all Entry objects with a Blog whose name is 'Beatles Blog': Entry.objects.filter(blog__name='Beatles Blog') Blog.objects.filter(entry__headline__contains='Lennon')
对同一表内不同的字段进行对比查询，In the examples given so far, we have constructed filters that compare the value of a model field with a constant. But what if you want to compare the value of a model field with another field on the same model?
Django provides F expressions to allow such comparisons. Instances of F() act as a reference to a model field within a query. These references can then be used in query filters to compare the values of two different fields on the same model instance.
For example, to find a list of all blog entries that have had more comments than pingbacks, we construct an F() object to reference the pingback count, and use that F() object in the query:
>>> from django.db.models import F >>> Entry.objects.filter(n_comments__gt=F('n_pingbacks'))
Django supports the use of addition, subtraction, multiplication, division, modulo, and power arithmetic with F() objects, both with constants and with other F() objects. To find all the blog entries with more than twice as many comments as pingbacks, we modify the query:
>>> Entry.objects.filter(n_comments__gt=F('n_pingbacks') * 2)
To find all the entries where the rating of the entry is less than the sum of the pingback count and comment count, we would issue the query:
>>> Entry.objects.filter(rating__lt=F('n_comments') + F('n_pingbacks'))
For date and date/time fields, you can add or subtract a timedelta object. The following would return all entries that were modified more than 3 days after they were published:
>>> from datetime import timedelta >>> Entry.objects.filter(mod_date__gt=F('pub_date') + timedelta(days=3))
Caching and QuerySets
Each QuerySet contains a cache to minimize database access. Understanding how it works will allow you to write the most efficient code.
In a newly created QuerySet, the cache is empty. The first time a QuerySet is evaluated – and, hence, a database query happens – Django saves the query results in the QuerySet’s cache and returns the results that have been explicitly requested (e.g., the next element, if the QuerySet is being iterated over). Subsequent evaluations of the QuerySet reuse the cached results.
Keep this caching behavior in mind, because it may bite you if you don’t use your QuerySets correctly. For example, the following will create two QuerySets, evaluate them, and throw them away:
>>> print([e.headline for e in Entry.objects.all()]) >>> print([e.pub_date for e in Entry.objects.all()])
That means the same database query will be executed twice, effectively doubling your database load. Also, there’s a possibility the two lists may not include the same database records, because an Entry may have been added or deleted in the split second between the two requests.
To avoid this problem, simply save the QuerySet and reuse it:
>>> queryset = Entry.objects.all() >>> print([p.headline for p in queryset]) # Evaluate the query set. >>> print([p.pub_date for p in queryset]) # Re-use the cache from the evaluation.
When QuerySets are not cached
Querysets do not always cache their results. When evaluating only part of the queryset, the cache is checked, but if it is not populated then the items returned by the subsequent query are not cached. Specifically, this means that limiting the querysetusing an array slice or an index will not populate the cache.
For example, repeatedly getting a certain index in a queryset object will query the database each time:
>>> queryset = Entry.objects.all() >>> print queryset[5] # Queries the database >>> print queryset[5] # Queries the database again
However, if the entire queryset has already been evaluated, the cache will be checked instead:
>>> queryset = Entry.objects.all() >>> [entry for entry in queryset] # Queries the database >>> print queryset[5] # Uses cache >>> print queryset[5] # Uses cache
Complex lookups with Q objects（复杂查询）
Keyword argument queries – in filter(), etc. – are “AND”ed together. If you need to execute more complex queries (for example, queries with OR statements), you can use Q objects.
A Q object (django.db.models.Q) is an object used to encapsulate a collection of keyword arguments. These keyword arguments are specified as in “Field lookups” above.
For example, this Q object encapsulates a single LIKE query:
from django.db.models import Q Q(question__startswith='What')
Q objects can be combined using the & and | operators. When an operator is used on two Q objects, it yields a new Q object.
For example, this statement yields a single Q object that represents the “OR” of two "question__startswith" queries:
Q(question__startswith='Who') | Q(question__startswith='What')
This is equivalent to the following SQL WHERE clause:
WHERE question LIKE 'Who%' OR question LIKE 'What%'
You can compose statements of arbitrary complexity by combining Q objects with the & and | operators and use parenthetical grouping. Also, Q objects can be negated using the ~ operator, allowing for combined lookups that combine both a normal query and a negated (NOT) query:
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
Each lookup function that takes keyword-arguments (e.g. filter(), exclude(), get()) can also be passed one or more Qobjects as positional (not-named) arguments. If you provide multiple Q object arguments to a lookup function, the arguments will be “AND”ed together. For example:
Poll.objects.get( Q(question__startswith='Who'), Q(pub_date=date(2005, 5, 2)) | Q(pub_date=date(2005, 5, 6)) )
... roughly translates into the SQL:
SELECT * from polls WHERE question LIKE 'Who%' AND (pub_date = '2005-05-02' OR pub_date = '2005-05-06')
Lookup functions can mix the use of Q objects and keyword arguments. All arguments provided to a lookup function (be they keyword arguments or Q objects) are “AND”ed together. However, if a Q object is provided, it must precede the definition of any keyword arguments. For example:
Poll.objects.get( Q(pub_date=date(2005, 5, 2)) | Q(pub_date=date(2005, 5, 6)), question__startswith='Who')
... would be a valid query, equivalent to the previous example; but:
# INVALID QUERY Poll.objects.get( question__startswith='Who', Q(pub_date=date(2005, 5, 2)) | Q(pub_date=date(2005, 5, 6)))
更新
Updating multiple objects at once
# Update all the headlines with pub_date in 2007. Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
在原有数据的基础上批量自增
Calls to update can also use F expressions to update one field based on the value of another field in the model. This is especially useful for incrementing counters based upon their current value. For example, to increment the pingback count for every entry in the blog:
>>> Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
However, unlike F() objects in filter and exclude clauses, you can’t introduce joins when you use F() objects in an update – you can only reference fields local to the model being updated. If you attempt to introduce a join with an F() object, a FieldErrorwill be raised:
# THIS WILL RAISE A FieldError >>> Entry.objects.update(headline=F('blog__name'))
Aggregation（聚合）
from django.db import models class Author(models.Model): name = models.CharField(max_length=100) age = models.IntegerField() class Publisher(models.Model): name = models.CharField(max_length=300) num_awards = models.IntegerField() class Book(models.Model): name = models.CharField(max_length=300) pages = models.IntegerField() price = models.DecimalField(max_digits=10, decimal_places=2) rating = models.FloatField() authors = models.ManyToManyField(Author) publisher = models.ForeignKey(Publisher) pubdate = models.DateField() class Store(models.Model): name = models.CharField(max_length=300) books = models.ManyToManyField(Book) registered_users = models.PositiveIntegerField() 示例models
# Total number of books. >>> Book.objects.count() # Total number of books with publisher=BaloneyPress >>> Book.objects.filter(publisher__name='BaloneyPress').count() # Average price across all books. >>> from django.db.models import Avg >>> Book.objects.all().aggregate(Avg('price')) {'price__avg': 34.35} # Max price across all books. >>> from django.db.models import Max >>> Book.objects.all().aggregate(Max('price')) {'price__max': Decimal('81.20')} # Cost per page >>> Book.objects.all().aggregate( ... price_per_page=Sum(F('price')/F('pages'), output_field=FloatField())) {'price_per_page': 0.4470664529184653} # All the following queries involve traversing the Book<->Publisher # foreign key relationship backwards. # Each publisher, each with a count of books as a "num_books" attribute. >>> from django.db.models import Count >>> pubs = Publisher.objects.annotate(num_books=Count('book')) >>> pubs [<Publisher BaloneyPress>, <Publisher SalamiPress>, ...] >>> pubs[0].num_books # The top 5 publishers, in order by number of books. >>> pubs = Publisher.objects.annotate(num_books=Count('book')).order_by('-num_books')[:5] >>> pubs[0].num_books 常用聚合场景需求
更多聚合查询例子:https://docs.djangoproject.com/en/1.9/topics/db/aggregation/
用户认证
from django.contrib.auth import authenticate user = authenticate(username='john', password='secret') if user is not None: # the password verified for the user if user.is_active: print("User is valid, active and authenticated") else: print("The password is valid, but the account has been disabled!") else: # the authentication system was unable to verify the username and password print("The username and password were incorrect.")
How to log a user out
from django.contrib.auth import logout def logout_view(request): logout(request) # Redirect to a success page.
