###### tags: `django`
# django入門(七) — 簡單範例(5)-Django ORM操作
## IT邦連結(需使用電腦版瀏覽器):[點我前往](https://ithelp.ithome.com.tw/users/20145754/articles)
全部文章:
[django入門(一) — 介紹與設定開發環境](https://hackmd.io/@aroncode/SkVeqBO2K)
[django入門(二) — 建立資料庫與專案](https://hackmd.io/@aroncode/rkqgL_unY)
[django入門(三) — 簡單範例(1)-建立app](https://hackmd.io/@aroncode/H1qirFdhF)
[django入門(四) — 簡單範例(2)-範本與範本繼承](https://hackmd.io/@aroncode/rkFuiwKnY)
[django入門(五) — 簡單範例(3)-靜態檔](https://hackmd.io/@aroncode/ByL4dFO2Y)
[django入門(六) — 資料模型與填充程式](https://hackmd.io/@aroncode/BJot2iRnF)
[django入門(七) — Django ORM操作](https://hackmd.io/@aroncode/SJec_hA3Y)
## Django ORM介紹
一般而言，我們要存取資料庫需要透過SQL語法，但在django則是使用ORM技術來存取資料庫，
django提供新增、刪除、修改、搜尋的方法給開發者，語法簡單且可防止SQL injection。
物件關聯對映(Object-relational mapping, ORM)，是一種程式設計技術，用於實現物件導向程式語言裡不同類型系統的資料之間的轉換。從效果上說，它其實是建立了一個可在程式語言裡使用的「虛擬物件資料庫」。如今已有很多免費和付費的ORM產品，而有些程式設計師更傾向於建立自己的ORM工具。
參考資料:[維基百科-ORM](https://zh.wikipedia.org/wiki/%E5%AF%B9%E8%B1%A1%E5%85%B3%E7%B3%BB%E6%98%A0%E5%B0%84)
## 新增
首先我們先在stock/templates/stock下建立一個stockCreate.html
stock/templates/stock/stockCreate.html
```
{% extends 'main/base.html' %}
{% block heading %}股票-新增{% endblock %}
{% block content %}
<form class="inlineBlock" method="post" action="{% url 'stock:stockCreate' %}">
{% csrf_token %}
<p>名稱:<input type="text" name="stockname" value="" required></p>
<p>股價:<input type="text" name="stockprice" value="" required></p>
<p>簡介:<input type="text" name="stockcontent" value="" required></p>
<input class="btn" type="submit" value="新增">
</form>
{% endblock %}
```
stock/views.py 加入套件與函式
```
import套件:
from django.contrib import messages
from django.shortcuts import render, redirect <-新增這個
```
```
def stockCreate(request):
stockCreatetemplate = 'stock/stockCreate.html'
if request.method == 'GET':
return render(request, stockCreatetemplate)
stockname = request.POST.get('stockname')
if stockname:
stockname = stockname.strip()
if not stockname:
return redirect('stock/stockCreate')
stockprice = request.POST.get('stockprice')
if stockprice:
stockprice = stockprice.strip()
if not stockprice:
return redirect('stock/stockCreate')
stockcontent = request.POST.get('stockcontent')
if stockcontent:
stockconetnt = stockcontent.strip()
if not stockcontent:
return redirect('stock/stockCreate')
Stock.objects.create(name=stockname, price=stockprice, content=stockcontent)
messages.success(request, '新增成功!')
return redirect('stock:stock')
```
stock/urls.py的urlpatterns加入以下路徑
```
path('stockCreate/', views.stockCreate, name='stockCreate')
```
## 刪除
stock/templates/stock/stock.html中的{% for stock in stocks %}區塊替換成以下
```
{% for stock in stocks %}
<div align="left">
<form style="display:inline" method="post" action="{% url 'stock:stockDelete' stock.id %}">
{% csrf_token %}
<input class="btn" type="submit" value="刪除">
</form>
<div>
<h3>名稱:{{ stock.name }}</h3>
<p>當前股價:{{ stock.price }}</p>
<p>簡介:{{ stock.content }}<p>
<hr>
</div>
</div>
{% endfor %}
```
stock/views.py
```
最上方既有的django.shortcuts再 import 一個 get_object_or_404
```
```
def stockDelete(request, stockId):
'''
Delete a comment:
1. Get the comment to update and its article; redirect to 404 if not found
2. If it is a 'GET' request, return
3. If the comment's author is not the user, return
4. Delete the comment
'''
stock = get_object_or_404(Stock, id=stockId)
stock.delete()
messages.success(request, '刪除成功!')
return redirect('stock:stock')
```
stock/urls.py的urlpatterns加入以下路徑
```
path('stockDelete/<int:stockId>/', views.stockDelete, name='stockDelete')
```
這裡的int:stockId是用來傳遞參數的。
## 搜尋
第一步於templates/stock 下建立一個stockSearch.html
這裡我們用範本標籤的寫法，因為有可能會有多個地方會用到搜尋這個功能，所以我們將搜尋表單獨立一個html，再透過{% include 'stock/stockSearch.html' %}放到我們需要用的地方。
stock/templates/stock/stock.html
```
...
<h2>{{ stock }}</h2>
{% include 'stock/stockSearch.html' %} <-加到這裡
<div align="right">
...
```
stock/views.py加入以下code
```
def stockSearch(request):
searchTerm = request.GET.get('searchTerm')
stocks = Stock.objects.filter(Q(name__icontains=searchTerm)|
Q(price__icontains=searchTerm)|
Q(content__icontains=searchTerm))
context = {'stock':'stock page','stocks':stocks, 'searchTerm':searchTerm}
return render(request, 'stock/stock.html', context)
```
stock/urls.py的urlpatterns加入以下路徑
```
path('stockSearch/', views.stockSearch, name='stockSearch')
```
## 修改
stock/templates/stock 下建立stockUpdate.html
stock/templates/stock/stockUpdate.html
```
{% extends 'main/base.html' %}
{% block heading %}股票-修改{% endblock %}
{% block content %}
<form class="inlineBlock" method="post" action="{% url 'stock:stockUpdate' stock.id %}">
{% csrf_token %}
<p>名稱:<input type="text" name="stockname" value="{{stock.name}}" required></p>
<p>股價:<input type="text" name="stockprice" value="{{stock.price}}" required></p>
<p>簡介:<input type="text" name="stockcontent" value="{{stock.content}}" required></p>
<input class="btn" type="submit" value="修改">
</form>
{% endblock %}
```
stock/views.py
```
def stockUpdate(request, stockId):
stock = get_object_or_404(Stock, id=stockId)
template = 'stock/stockUpdate.html'
if request.method == 'GET':
context={'stock':stock
}
return render(request, template,context)
# POST
stockname = request.POST.get('stockname')
stockprice = request.POST.get('stockprice')
stockcontent = request.POST.get('stockcontent')
stock.name=stockname
stock.price=stockprice
stock.content=stockcontent
stock.save()
messages.success(request, '修改成功!')
return redirect('stock:stock')
```
stock/urls.py的urlpatterns加入以下路徑
```
path('stockUpdate/<int:stockId>/', views.stockUpdate, name='stockUpdate')
```
## 補充語法(以Stock model為例)
### 新增
1.Stock.objects.create(...)
2.
stock = Stock()
stock.name="台積電"
stock.price=670
..
stock.save()
### 搜尋
Stock.objects.all()
Stock.objects.get(...)
Stock.objects.filter(...)
Stock.objects.exclude(...)
Stock.objects.order_by(...)
Stock.objects.filter(...).order_by(...)
### 刪除
stock = Stock.objects.get(...)
stock.delete()
### 更新
stock = Stock.objects.get(...)
stock.name="台積電"
stock.price=670
..
stock.save()
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