解析Dragonboard 410c搭載web服務(wù)器之?dāng)?shù)據(jù)庫的設(shè)計(jì)

一.前言

在經(jīng)過上篇《Dragonboard410c 服務(wù)器系列六之用戶交互系統(tǒng)》的學(xué)習(xí)，博主相信大家都能大致掌握Django框架基礎(chǔ)的web服務(wù)器搭建以及簡單的數(shù)據(jù)交互。但是，往深處想，Django是如何存儲不同頁面的交互數(shù)據(jù)的?相信有看過博主之前上傳的代碼的童鞋都已經(jīng)知曉，這也是我們今天要討論的主題：數(shù)據(jù)庫。

二.數(shù)據(jù)庫

1.概念：

數(shù)據(jù)庫(Database)是按照數(shù)據(jù)結(jié)構(gòu)來組織、存儲和管理數(shù)據(jù)的建立在計(jì)算機(jī)存儲設(shè)備上的倉庫。簡單來說是本身可視為電子化的文件柜——存儲電子文件的處所，用戶可以對文件中的數(shù)據(jù)進(jìn)行新增、截取、更新、刪除等操作。在經(jīng)濟(jì)管理的日常工作中，常常需要把某些相關(guān)的數(shù)據(jù)放進(jìn)這樣的“倉庫”，并根據(jù)管理的需要進(jìn)行相應(yīng)的處理?？梢哉f數(shù)據(jù)庫的設(shè)計(jì)是web后臺架構(gòu)設(shè)計(jì)的重中之重，合理的數(shù)據(jù)庫設(shè)計(jì)將會為后臺節(jié)省大量的運(yùn)算步驟和提高整體的運(yùn)行效率，這也是衡量一個(gè)后臺工程師功底的重要標(biāo)準(zhǔn)。

2.Django的數(shù)據(jù)庫：

2.1.介紹：

Django的數(shù)據(jù)庫，我們稱之為模型，與數(shù)據(jù)庫相關(guān)的代碼一般寫在 models.py 中，Django 支持 sqlite3， MySQL， PostgreSQL等數(shù)據(jù)庫，只需要在setTIngs.py中配置即可，不用更改models.py中的代碼，豐富的API極大的方便了使用。當(dāng)然，我們也可以根據(jù)自己的需要去自定義filed，也就是自己的模型。比如上篇的用戶交互系統(tǒng)，我們就不僅繼承的原有MyUser，還自定義了消息的模型：online_message以及系統(tǒng)的狀態(tài)模型：online_SystemStatus.

2.2 創(chuàng)建步驟：

2.2.1.創(chuàng)建django項(xiàng)目：

django-admin startproject test

2.2.2.創(chuàng)建webapp：

cd test

django-admin startapp sql

2.2.3.添加webapp進(jìn)test項(xiàng)目：

vim test/test/setTIngs.py

INSTALLED_APPS = (

'django.contrib.admin',

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.messages',

'django.contrib.staTIcfiles',

'sql',

)

2.2.4.定義sql的數(shù)據(jù)模型：

from django.db import models

class Person(models.Model):

name = models.CharField(max_length=30)

age = models.IntegerField()

2.2.5.初始化數(shù)據(jù)庫數(shù)據(jù)：

cd ~/test

python manage.py makemigraTIons sql

python manage.py migrate

3.實(shí)例模型代碼：

#coding:utf8

from django.db import models

from django.contrib.auth.models import (

BaseUserManager, AbstractBaseUser, PermissionsMixin)

class MyUserManager(BaseUserManager):

# def _create_user(self, username, email, password, **extra_fields):

def _create_user(self, username, password, **extra_fields):

"""

Creates and saves a User with the given username, email and password.

"""

if not username:

raise ValueError('The given username must be set')

# email = self.normalize_email(email)

# user = self.model(username=username, email=email, **extra_fields)

user = self.model(username=username, **extra_fields)

user.set_password(password)

user.save(using=self._db)

return user

# def create_user(self, username, email, password, **extra_fields):

def create_user(self, username, password, **extra_fields):

extra_fields.setdefault('is_staff', False)

extra_fields.setdefault('email',"")

extra_fields.setdefault('phone',"")

extra_fields.setdefault('haarValue',"")

extra_fields.setdefault('avatarImg',"")

# extra_fields.setdefault('text',"")

# extra_fields.setdefault('video',"")

# extra_fields.setdefault('time',"")

return self._create_user(username, password, **extra_fields)

# return self._create_user(username, email, password, **extra_fields)

# def create_superuser(self, username, email, password, **extra_fields):

def create_superuser(self, username, password, **extra_fields):

extra_fields.setdefault('is_staff', True)

if extra_fields.get('is_staff') is not True:

raise ValueError('Superuser must have is_staff=True')

#拓展user數(shù)據(jù) by xiao

#get

#to

#message_flag

#text

#video

#time

# extra_fields.setdefault('got',username)

# extra_fields.setdefault('to',username)

# extra_fields.setdefault('message_flag',"1")

# extra_fields.setdefault('text',"")

# extra_fields.setdefault('video',"")

# extra_fields.setdefault('time',"")

return self._create_user(username, password, **extra_fields)

# return self._create_user(username, email, password, **extra_fields)

class MyUser(AbstractBaseUser, PermissionsMixin):

username = models.CharField(max_length=254, unique=True, db_index=True)

email = models.CharField(max_length=254)

phone = models.CharField(max_length=254)

haarValue = models.CharField(max_length=254)

avatarImg = models.CharField(max_length=254)

#email = models.EmailField('email address', max_length=254)[!--empirenews.page--]

#text=models.CharField(max_length=254, unique=True, db_index=True)

is_staff = models.BooleanField('staff status', default=False)

# userID = models.IntegerField(default=1) #用戶獨(dú)有的ID

# is_active = models.BooleanField('active', default=True)

# got = models.CharField(max_length=254,default=username)

# to = models.CharField(max_length=254,default=username)

# message_flag = models.CharField(max_length=254, default=1)

# text = models.CharField(max_length=254, default="")

# video = models.CharField(max_length=254,default="")

# time = models.CharField(max_length=254,default="")

USERNAME_FIELD = 'username'

# REQUIRED_FIELDS = ['email']

objects = MyUserManager()

class Meta:

db_table = 'myuser'

# def get_full_name(self):

# return self.username

# def get_short_name(self):

# return self.username

#建立推送消息的模型

class Message(models.Model):

# username = models.CharField(max_length=254) #消息推送者的名字

ownerID = models.IntegerField(default=1)

pushID = models.IntegerField(default=1)

infoType = models.IntegerField(default=0)

infoSubject = models.CharField(max_length=254)

infoContent = models.CharField(max_length=254)

filePath = models.CharField(max_length=1000)

pushTim = models.CharField(max_length=254)

infoValidityTime = models.CharField(max_length=254)

isTop = models.IntegerField(default=0)

viewWeight = models.IntegerField(default=1)

def __unicode__(self):

# 在Python3中使用 def __str__(self)

return self.name

class SystemStatus(models.Model): #實(shí)例化對象：online_message MMDB.updateSystemStatus('peopleInfront',-1,0,'no people in front')

statusName = models.CharField(max_length=30,default="peopleInfront")

statusValue = models.IntegerField(default=-1)

statusParam = models.IntegerField(default=0)

statusDiscirption = models.CharField(max_length=50,default="no people in front")

def __unicode__(self):

# 在Python3中使用 def __str__(self)

return self.name

三.例程分享：http://pan.baidu.com/share/link?shareid=3536829173&uk=1812979481