如何用Django建立一个后台CRM系统02

往数据库中添加数据 在Teminal对数据库进行操作

　　-objects.all查找

　　-objects.first  获取表中对象（即一行）

　　-xxxx .order_set.all 反向查询 一般是从父程序查询子程序 即知道一个对象的具体属性xxxx 通过外键关联  反找出另一个表的数据

像最后的父子模型

#***(1)Returns all customers from customer table
customers = Customer.objects.all()

#(2)Returns first customer in table
firstCustomer = Customer.objects.first()

#(3)Returns last customer in table
lastCustomer = Customer.objects.last()

#(4)Returns single customer by name
customerByName = Customer.objects.get(name='Peter Piper')

#***(5)Returns single customer by name
customerById = Customer.objects.get(id=4)

#***(6)Returns all orders related to customer (firstCustomer variable set above)
firstCustomer.order_set.all()

#(7)***Returns orders customer name: (Query parent model values)
order = Order.objects.first() 
parentName = order.customer.name

#(8)***Returns products from products table with value of "Out Door" in category attribute
products = Product.objects.filter(category="Out Door")

#(9)***Order/Sort Objects by id
leastToGreatest = Product.objects.all().order_by('id') 
greatestToLeast = Product.objects.all().order_by('-id') 


#(10) Returns all products with tag of "Sports": (Query Many to Many Fields)
productsFiltered = Product.objects.filter(tags__name="Sports")

'''
(11)Bonus
Q: If the customer has more than 1 ball, how would you reflect it in the database?
A: Because there are many different products and this value changes constantly you would most 
likly not want to store the value in the database but rather just make this a function we can run
each time we load the customers profile
'''

#Returns the total count for number of time a "Ball" was ordered by the first customer
ballOrders = firstCustomer.order_set.filter(product__name="Ball").count()

#Returns total count for each product orderd
allOrders = {}

for order in firstCustomer.order_set.all():
    if order.product.name in allOrders:
        allOrders[order.product.name] += 1
    else:
        allOrders[order.product.name] = 1

#Returns: allOrders: {'Ball': 2, 'BBQ Grill': 1}


#RELATED SET EXAMPLE
class ParentModel(models.Model):
    name = models.CharField(max_length=200, null=True)

class ChildModel(models.Model):
    parent = models.ForeignKey(Customer)
    name = models.CharField(max_length=200, null=True)

parent = ParentModel.objects.first()
#Returns all child models related to parent
parent.childmodel_set.all()

对于动态路由（正则）：

　　-在path  <>里面加入primary key  <str:pk>

 path('customer/<str:pk>/', views.customer,name='customer'),

　　-向函数里面传参数

def customer(request, pk):

对模板进行动态数据的输入和url路由

　　　　-{{ xxx }} 是模板里动态对数据的输入填充   

　　　　　　其中值得注意的是在函数中对数据库取值时利用反向传参求得数据（父子模型）             -在多项选择中过滤选项

order = customer.order_set.all()
<td>{{order.customer.name}}</td>

Dlivered = order.objects.filter(status='Dlivered')   //status是html页面 dlivered是其中一个多项选择

　　　　-{% for i in date %} 可用于循环结构

   　　　　　　href ="{%  url 'customer' customer.id  %}" id是用get传参数给customer的primary key

{% for customer in customers %}
                    <tr>
                        <td><a class="btn btn-sm btn-info" href="{% url 'customer' customer.id %}">View</a></td>
                        <td>{{customer.name}}</td>
                        <td>{{customer.phone}}</td>
                    </tr>
  {% endfor %}　　　　　　　

　　　　-{%  url  'xxx'  % }　用于url的跳转  <a  href = "{ % url  'xxx' %}"></a>   （其中xxx为url的name）

　　　　　　需要在url.py中在path后面加上name

 path('',views.home,name='home'),
    path('products/',views.products,name='products'),
    path('customer/<str:pk>/', views.customer,name='customer'),

　　　　　　在html中的a标签里面的href属性设置跳转

<td> 
  <a class="btn btn-sm btn-info" href="{% url'customer'customer.id%}">
Views
  </a>
</td>