1，在Django项目的settings.py，文件中，配置数据库连接信息：
2，在Django项目中__init__.py文件中写如下代码，告诉Django使用pyMysqL模块连接MysqL数据库：
二，Model
在Django中model是你数据的单一、明确的信息来源。它包含了你存储的数据的重要字段和行为。通常，一个模型（model）映射到一个数据库表，
基本情况：
三，快速入门
下面这个例子定义了一个 Person 模型，包含 first_name 和 last_name。
class Person(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)
first_name 和 last_name 是模型的字段。每个字段被指定为一个类属性，每个属性映射到一个数据库列。
一些说明：
- 表myapp_person的名称是自动生成的，如果你要自定义表名，需要在model的Meta类中指定 db_table 参数，强烈建议使用小写表名，特别是使用MysqL作为后端数据库时。
- id字段是自动添加的，如果你想要指定自定义主键，只需在其中一个字段中指定 primary_key=True 即可。如果Django发现你已经明确地设置了Field.primary_key，它将不会添加自动ID列。
- 本示例中的CREATE TABLE sql使用Postgresql语法进行格式化，但值得注意的是，Django会根据配置文件中指定的数据库后端类型来生成相应的sql语句。
- Django支持MysqL5.5及更高版本。
四，字段
BigAutoField(AutoField)
</span>- bigint自增列，必须填入参数 primary_key=<span style="color: #000000">True
注：当model中如果没有自增列，则<a href="/tag/zidong/" target="_blank" class="keywords">自动</a>会创建<a href="/tag/yige/" target="_blank" class="keywords">一个</a>列名为id的列
</span><span style="color: #0000ff">from</span> django.db <span style="color: #0000ff">import</span><span style="color: #000000"> models
</span><span style="color: #0000ff">class</span><span style="color: #000000"> UserInfo(models.Model):
</span><span style="color: #008000">#</span><span style="color: #008000"> <a href="/tag/zidong/" target="_blank" class="keywords">自动</a>创建<a href="/tag/yige/" target="_blank" class="keywords">一个</a>列名为id的且为自增的整数列</span>
username = models.CharField(max_length=32<span style="color: #000000">)
</span><span style="color: #0000ff">class</span><span style="color: #000000"> Group(models.Model):
</span><span style="color: #008000">#</span><span style="color: #008000"> <a href="/tag/zidingyi/" target="_blank" class="keywords">自定义</a>自增列</span>
nid = models.AutoField(primary_key=<span style="color: #000000">True)
name </span>= models.CharField(max_length=32<span style="color: #000000">)
SmallIntegerField(IntegerField):
</span>- 小整数 -32768 ～ 32767<span style="color: #000000">
PositiveSmallIntegerField(PositiveIntegerRelDbTypeMixin,IntegerField)
</span>- 正小整数 0 ～ 32767<span style="color: #000000">
IntegerField(Field)
</span>- 整数列(有符号的) -2147483648 ～ 2147483647<span style="color: #000000">
PositiveIntegerField(PositiveIntegerRelDbTypeMixin,IntegerField)
</span>- 正整数 0 ～ 2147483647<span style="color: #000000">
BigIntegerField(IntegerField):
</span>- 长整型(有符号的) -9223372036854775808 ～ 9223372036854775807<span style="color: #000000">
BooleanField(Field)
</span>-<span style="color: #000000"> 布尔值类型
NullBooleanField(Field):
</span>-<span style="color: #000000"> 可以为空的布尔值
CharField(Field)
</span>-<span style="color: #000000"> 字符类型
</span>-<span style="color: #000000"> 必须提供max_length参数， max_length表示字符长度
TextField(Field)
</span>-<span style="color: #000000"> 文本类型
EmailField(CharField)：
</span>-<span style="color: #000000"> 字符串类型，Django Admin以及ModelForm中提供验证机制
IPAddressField(Field)
</span>-<span style="color: #000000"> 字符串类型，Django Admin以及ModelForm中提供验证 IPV4 机制
GenericIPAddressField(Field)
</span>-<span style="color: #000000"> 字符串类型，Django Admin以及ModelForm中提供验证 Ipv4和Ipv6
</span>-<span style="color: #000000"> 参数：
protocol，用于指定Ipv4或Ipv6， </span><span style="color: #800000">'</span><span style="color: #800000">both</span><span style="color: #800000">'</span>,<span style="color: #800000">"</span><span style="color: #800000">ipv4</span><span style="color: #800000">"</span>,<span style="color: #800000">"</span><span style="color: #800000">ipv6</span><span style="color: #800000">"</span><span style="color: #000000">
unpack_ipv4， 如果指定为True，则输入::ffff:</span>192.0.2.1时候，可解析为192.0.2.1，开启此<a href="/tag/gongneng/" target="_blank" class="keywords">功能</a>，需要protocol=<span style="color: #800000">"</span><span style="color: #800000">both</span><span style="color: #800000">"</span><span style="color: #000000">
URLField(CharField)
</span>-<span style="color: #000000"> 字符串类型，Django Admin以及ModelForm中提供验证 URL
SlugField(CharField)
</span>-<span style="color: #000000"> 字符串类型，Django Admin以及ModelForm中提供验证<a href="/tag/zhichi/" target="_blank" class="keywords">支持</a> 字母、数字、下划线、连接符（减号）
CommaSep<a href="/tag/ara/" target="_blank" class="keywords">ara</a>tedIntegerField(CharField)
</span>-<span style="color: #000000"> 字符串类型，格式必须为逗号分割的数字
UUIDField(Field)
</span>-<span style="color: #000000"> 字符串类型，Django Admin以及ModelForm中提供对UUID格式的验证
FilePathField(Field)
</span>-<span style="color: #000000"> 字符串，Django Admin以及ModelForm中提供读取<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>夹下<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>的<a href="/tag/gongneng/" target="_blank" class="keywords">功能</a>
</span>-<span style="color: #000000"> 参数：
path,<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>夹路径
match</span>=<span style="color: #000000">None,正则匹配
recursive</span>=<span style="color: #000000">False,递归下面的<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>夹
allow_files</span>=<span style="color: #000000">True,允许<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>
allow_folders</span>=<span style="color: #000000">False,允许<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>夹
FileField(Field)
</span>-<span style="color: #000000"> 字符串，路径保存在<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>，<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a><a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a>到指定目录
</span>-<span style="color: #000000"> 参数：
upload_to </span>= <span style="color: #800000">""</span><span style="color: #000000"> <a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a><a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>的保存路径
storage </span>=<span style="color: #000000"> None 存储组件，<a href="/tag/mo/" target="_blank" class="keywords">默</a>认django.core.files.storage.FileSy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>Storage
ImageField(FileField)
</span>-<span style="color: #000000"> 字符串，路径保存在<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>，<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a><a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a>到指定目录
</span>-<span style="color: #000000"> 参数：
upload_to </span>= <span style="color: #800000">""</span><span style="color: #000000"> <a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a><a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>的保存路径
storage </span>=<span style="color: #000000"> None 存储组件，<a href="/tag/mo/" target="_blank" class="keywords">默</a>认django.core.files.storage.FileSy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>Storage
width_field</span>=<span style="color: #000000">None,<a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a><a href="/tag/tupian/" target="_blank" class="keywords">图片</a>的高度保存的<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>字段名（字符串）
height_field</span>=<span style="color: #000000">None <a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a><a href="/tag/tupian/" target="_blank" class="keywords">图片</a>的宽度保存的<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>字段名（字符串）
DateTimeField(DateField)
</span>- 日期+时间格式 YYYY-MM-<span style="color: #000000">DD HH:MM[:ss[.uuuuuu]][TZ]
DateField(DateTimeCheckMixin,Field)
</span>- 日期格式 YYYY-MM-<span style="color: #000000">DD
TimeField(DateTimeCheckMixin,Field)
</span>-<span style="color: #000000"> 时间格式 HH:MM[:ss[.uuuuuu]]
DurationField(Field)
</span>-<span style="color: #000000"> <a href="/tag/changzhengshu/" target="_blank" class="keywords">长整数</a>，时间间隔，<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>中按照bigint存储，ORM中<a href="/tag/huoqu/" target="_blank" class="keywords">获取</a>的值为datetime.<a href="/tag/timedelta/" target="_blank" class="keywords">timedelta</a>类型
FloatField(Field)
</span>-<span style="color: #000000"> 浮点型
DecimalField(Field)
</span>-<span style="color: #000000"> 10进制小数
</span>-<span style="color: #000000"> 参数：
max_digits，小数总长度
decimal_places，小数位长度
BinaryField(Field)
</span>-<span style="color: #000000"> 二进制类型
字段相关内容
1，常用字段
1）AutoField
int自增列，必须填入参数 primary_key=True。当model中如果没有自增列，则自动会创建一个列名为id的列。
2）IntegerField
一个整数类型,范围在 -2147483648 to 2147483647
3）CharField
字符类型，必须提供max_length参数， max_length表示字符长度。
4）DateField
日期字段，日期格式 YYYY-MM-DD，相当于Python中的datetime.date()实例
5）DateTimeField
日期时间字段，格式 YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ]，相当于Python中的datetime.datetime()实例。
五，自定义字段
</span><span style="color: #0000ff">def</span><span style="color: #000000"> db_type(self,connection):
</span><span style="color: #800000">"""</span><span style="color: #800000">
限定<a href="/tag/shengcheng/" target="_blank" class="keywords">生成</a><a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>表的字段类型为char，长度为max_length指定的值
</span><span style="color: #800000">"""</span>
<span style="color: #0000ff">return</span> <span style="color: #800000">'</span><span style="color: #800000">char(<a href="/tag/s/" target="_blank" class="keywords">%s</a>)</span><span style="color: #800000">'</span> %<span style="color: #000000"> self.max_lengthid = models.AutoField(primary_key=<span style="color: #000000">True)
title = models.CharField(max_length=25<span style="color: #000000">)
<span style="color: #008000">#<span style="color: #008000"> 使用自定义的char类型的字段
cname = FixedCharField(max_length=25)
六，注意事项
email </span>= models.EmailField(error_messages={<span style="color: #800000">'</span><span style="color: #800000">invalid</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">格式错了.</span><span style="color: #800000">'</span><span style="color: #000000">})
</span><span style="color: #008000">#</span><span style="color: #008000"> views.py</span>
<span style="color: #0000ff">def</span><span style="color: #000000"> index(request):
obj </span>= models.UserInfo(username=<span style="color: #800000">'</span><span style="color: #800000">11234</span><span style="color: #800000">'</span>,email=<span style="color: #800000">'</span><span style="color: #800000">uu</span><span style="color: #800000">'</span><span style="color: #000000">)
</span><span style="color: #0000ff">try</span><span style="color: #000000">:
</span><span style="color: #0000ff">print</span><span style="color: #000000">(obj.clean_fields())
</span><span style="color: #0000ff">except</span><span style="color: #000000"> Exception as e:
</span><span style="color: #0000ff">print</span><span style="color: #000000">(e)
</span><span style="color: #0000ff">return</span> HttpResponse(<span style="color: #800000">'</span><span style="color: #800000">ok</span><span style="color: #800000">'</span><span style="color: #000000">)
</span><span style="color: #008000">#</span><span style="color: #008000"> Model的clean<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>是<a href="/tag/yige/" target="_blank" class="keywords">一个</a>钩子，可用于定制操作，如：上述的异常处理。</span>
2<span style="color: #000000">.Admin中<a href="/tag/xiugai/" target="_blank" class="keywords">修改</a><a href="/tag/cuowu/" target="_blank" class="keywords">错误</a><a href="/tag/tishi/" target="_blank" class="keywords">提示</a>
</span><span style="color: #008000">#</span><span style="color: #008000"> admin.py</span>
<span style="color: #0000ff">from</span> django.contrib <span style="color: #0000ff">import</span><span style="color: #000000"> admin
</span><span style="color: #0000ff">from</span> model_club <span style="color: #0000ff">import</span><span style="color: #000000"> models
</span><span style="color: #0000ff">from</span> django <span style="color: #0000ff">import</span><span style="color: #000000"> forms
</span><span style="color: #0000ff">class</span><span style="color: #000000"> UserInfoForm(forms.ModelForm):
age </span>= forms.IntegerField(initial=1,error_messages={<span style="color: #800000">'</span><span style="color: #800000"><a href="/tag/required/" target="_blank" class="keywords">required</a></span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">请输入数值.</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">invalid</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">年龄必须为数值.</span><span style="color: #800000">'</span><span style="color: #000000">})
</span><span style="color: #0000ff">class</span><span style="color: #000000"> <a href="/tag/Meta/" target="_blank" class="keywords">Meta</a>:
model </span>=<span style="color: #000000"> models.UserInfo
</span><span style="color: #008000">#</span><span style="color: #008000"> fields = ('username',)</span>
fields = <span style="color: #800000">"</span><span style="color: #800000">__all__</span><span style="color: #800000">"</span><span style="color: #000000">
exclude </span>= [<span style="color: #800000">'</span><span style="color: #800000">title</span><span style="color: #800000">'</span><span style="color: #000000">]
labels </span>= { <span style="color: #800000">'</span><span style="color: #800000">name</span><span style="color: #800000">'</span>:<span style="color: #800000">'</span><span style="color: #800000">Writer</span><span style="color: #800000">'</span><span style="color: #000000">,}
help_texts </span>= {<span style="color: #800000">'</span><span style="color: #800000">name</span><span style="color: #800000">'</span>:<span style="color: #800000">'</span><span style="color: #800000">some useful help text.</span><span style="color: #800000">'</span><span style="color: #000000">,}
error_messages</span>={ <span style="color: #800000">'</span><span style="color: #800000">name</span><span style="color: #800000">'</span>:{<span style="color: #800000">'</span><span style="color: #800000">max_length</span><span style="color: #800000">'</span>:<span style="color: #800000">"</span><span style="color: #800000">this writer name is too long</span><span style="color: #800000">"</span><span style="color: #000000">} }
widgets</span>={<span style="color: #800000">'</span><span style="color: #800000">name</span><span style="color: #800000">'</span>:Textarea(attrs={<span style="color: #800000">'</span><span style="color: #800000">cols</span><span style="color: #800000">'</span>:80,<span style="color: #800000">'</span><span style="color: #800000">rows</span><span style="color: #800000">'</span>:20<span style="color: #000000">})}
</span><span style="color: #0000ff">class</span><span style="color: #000000"> UserInfoAdmin(admin.ModelAdmin):
form </span>=<span style="color: #000000"> UserInfoForm
admin.site.register(models.UserInfo,UserInfoAdmin)
注意事项
七，字段参数
verbose_name Admin中<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>的字段<a href="/tag/mingcheng/" target="_blank" class="keywords">名称</a>
blank Admin中是否允许<a href="/tag/yonghu/" target="_blank" class="keywords">用户</a>输入为空
editable Admin中是否可以编辑
help_text Admin中该字段的<a href="/tag/tishi/" target="_blank" class="keywords">提示</a>信息
choices Admin中<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>选择框的<a href="/tag/neirong/" target="_blank" class="keywords">内容</a>，用不变动的数据放在内存中从而避免跨表操作
如：gf </span>= models.IntegerField(choices=[(0,<span style="color: #800000">'</span><span style="color: #800000">何穗</span><span style="color: #800000">'</span>),(1,<span style="color: #800000">'</span><span style="color: #800000">大表姐</span><span style="color: #800000">'</span>),],default=1<span style="color: #000000">)
error_messages <a href="/tag/zidingyi/" target="_blank" class="keywords">自定义</a><a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>信息（字典类型），从而定制想要<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>的<a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>信息；
字典健：null,blank,invalid,invalid_choice,unique,</span><span style="color: #0000ff">and</span><span style="color: #000000"> unique_for_date
如：{</span><span style="color: #800000">'</span><span style="color: #800000">null</span><span style="color: #800000">'</span>: <span style="color: #800000">"</span><span style="color: #800000">不能为空.</span><span style="color: #800000">"</span>,<span style="color: #800000">'</span><span style="color: #800000">invalid</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">格式<a href="/tag/cuowu/" target="_blank" class="keywords">错误</a></span><span style="color: #800000">'</span><span style="color: #000000">}
validators <a href="/tag/zidingyi/" target="_blank" class="keywords">自定义</a><a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>验证（列表类型），从而定制想要的验证规则
</span><span style="color: #0000ff">from</span> django.core.validators <span style="color: #0000ff">import</span><span style="color: #000000"> RegexValidator
</span><span style="color: #0000ff">from</span> django.core.validators <span style="color: #0000ff">import</span><span style="color: #000000"> EmailValidator,URLValidator,DecimalValidator,\
MaxLengthValidator,MinLengthValidator,MaxValueValidator,MinValueValidator
如：
test </span>=<span style="color: #000000"> models.CharField(
max_length</span>=32<span style="color: #000000">,error_messages</span>=<span style="color: #000000">{
</span><span style="color: #800000">'</span><span style="color: #800000">c1</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">优先错信息1</span><span style="color: #800000">'</span><span style="color: #000000">,</span><span style="color: #800000">'</span><span style="color: #800000">c2</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">优先错信息2</span><span style="color: #800000">'</span><span style="color: #000000">,</span><span style="color: #800000">'</span><span style="color: #800000">c3</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">优先错信息3</span><span style="color: #800000">'</span><span style="color: #000000">,},validators</span>=<span style="color: #000000">[
RegexValidator(regex</span>=<span style="color: #800000">'</span><span style="color: #800000">root_\d+</span><span style="color: #800000">'</span>,message=<span style="color: #800000">'</span><span style="color: #800000"><a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>了</span><span style="color: #800000">'</span>,code=<span style="color: #800000">'</span><span style="color: #800000">c1</span><span style="color: #800000">'</span><span style="color: #000000">),RegexValidator(regex</span>=<span style="color: #800000">'</span><span style="color: #800000">root_112233\d+</span><span style="color: #800000">'</span>,message=<span style="color: #800000">'</span><span style="color: #800000">又<a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>了</span><span style="color: #800000">'</span>,code=<span style="color: #800000">'</span><span style="color: #800000">c2</span><span style="color: #800000">'</span><span style="color: #000000">),EmailValidator(message</span>=<span style="color: #800000">'</span><span style="color: #800000">又<a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>了</span><span style="color: #800000">'</span>,code=<span style="color: #800000">'</span><span style="color: #800000">c3</span><span style="color: #800000">'</span><span style="color: #000000">),]
)字段参数
八，元信息
<span style="color: #008000">#</span><span style="color: #008000"> 联合索引</span>
index_together =<span style="color: #000000"> [
(</span><span style="color: #800000">"</span><span style="color: #800000">pub_date</span><span style="color: #800000">"</span>,<span style="color: #800000">"</span><span style="color: #800000">deadline</span><span style="color: #800000">"</span><span style="color: #000000">),]
</span><span style="color: #008000">#</span><span style="color: #008000"> 联合唯一索引</span>
unique_together = ((<span style="color: #800000">"</span><span style="color: #800000">driver</span><span style="color: #800000">"</span>,<span style="color: #800000">"</span><span style="color: #800000">restaurant</span><span style="color: #800000">"</span><span style="color: #000000">),)
</span><span style="color: #008000">#</span><span style="color: #008000"> admin中<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>的表<a href="/tag/mingcheng/" target="_blank" class="keywords">名称</a></span><span style="color: #000000"> verbose_name
</span><span style="color: #008000">#</span><span style="color: #008000"> verbose_name加s</span><span style="color: #000000"> verbose_name_plural
元信息
九，多表关系和参数
</span><span style="color: #0000ff">def</span><span style="color: #000000"> func():
</span><span style="color: #0000ff">return</span> 10
<span style="color: #0000ff">class</span><span style="color: #000000"> MyModel(models.Model):
user </span>=<span style="color: #000000"> models.ForeignKey(
to</span>=<span style="color: #800000">"</span><span style="color: #800000">User</span><span style="color: #800000">"</span><span style="color: #000000">,to_field</span>=<span style="color: #800000">"</span><span style="color: #800000">id</span><span style="color: #800000">"</span><span style="color: #000000">
on_delete</span>=<span style="color: #000000">models.SET(func),)
related_name</span>=None,<span style="color: #008000">#</span><span style="color: #008000"> 反向操作时，使用的字段名，用于代替 【表名_set】 如： obj.表名_set.all()</span>
related_query_name=None,<span style="color: #008000">#</span><span style="color: #008000"> 反向操作时，使用的连接前缀，用于替换【表名】 如： models.UserGroup.objects.filter(表名__字段名=1).values('表名__字段名')</span>
limit_choices_to=None,<span style="color: #008000">#</span><span style="color: #008000"> 在Admin或ModelForm中<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>关联数据时，提供的条件：</span>
<span style="color: #008000">#</span><span style="color: #008000"> 如：</span>
- limit_choices_to={<span style="color: #800000">'</span><span style="color: #800000">nid__gt</span><span style="color: #800000">'</span>: 5<span style="color: #000000">}
</span>- limit_choices_to=<span style="color: #0000ff">lambda</span> : {<span style="color: #800000">'</span><span style="color: #800000">nid__gt</span><span style="color: #800000">'</span>: 5<span style="color: #000000">}
</span><span style="color: #0000ff">from</span> django.db.models <span style="color: #0000ff">import</span><span style="color: #000000"> Q
</span>- limit_choices_to=Q(nid__gt=10<span style="color: #000000">)
</span>- limit_choices_to=Q(nid=8) | Q(nid__gt=10<span style="color: #000000">)
</span>- limit_choices_to=<span style="color: #0000ff">lambda</span> : Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption=<span style="color: #800000">'</span><span style="color: #800000">root</span><span style="color: #800000">'</span><span style="color: #000000">)
db_constraint</span>=True <span style="color: #008000">#</span><span style="color: #008000"> 是否在<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>中创建外键约束</span>
parent_link=False <span style="color: #008000">#</span><span style="color: #008000"> 在Admin中是否<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>关联数据</span><span style="color: #000000">
On<a href="/tag/eto/" target="_blank" class="keywords">eto</a>OneField(ForeignKey)
to,</span><span style="color: #008000">#</span><span style="color: #008000"> 要进行关联的表名</span>
to_field=None <span style="color: #008000">#</span><span style="color: #008000"> 要关联的表中的字段<a href="/tag/mingcheng/" target="_blank" class="keywords">名称</a></span>
on_delete=None,<span style="color: #008000">#</span><span style="color: #008000"> 当<a href="/tag/shanchu/" target="_blank" class="keywords">删除</a>关联表中的数据时，当前表与其关联的行的行为</span>
<span style="color: #008000">#</span><span style="color: #008000">##### 对于一对一 ######</span>
<span style="color: #008000">#</span><span style="color: #008000"> 1. 一对一其实就是 一对多 + 唯一索引</span>
<span style="color: #008000">#</span><span style="color: #008000"> 2.当两个类之间有继承关系时，<a href="/tag/mo/" target="_blank" class="keywords">默</a>认会创建<a href="/tag/yige/" target="_blank" class="keywords">一个</a>一对一字段</span>
<span style="color: #008000">#</span><span style="color: #008000"> 如下会在A表中额外<a href="/tag/zengjia/" target="_blank" class="keywords">增加</a><a href="/tag/yige/" target="_blank" class="keywords">一个</a>c_ptr_id列且唯一：</span>
<span style="color: #0000ff">class</span><span style="color: #000000"> C(models.Model):
nid </span>= models.AutoField(primary_key=<span style="color: #000000">True)
part </span>= models.CharField(max_length=12<span style="color: #000000">)
</span><span style="color: #0000ff">class</span><span style="color: #000000"> A(C):
id </span>= models.AutoField(primary_key=<span style="color: #000000">True)
code </span>= models.CharField(max_length=1<span style="color: #000000">)
ManyToManyField(RelatedField)
to,</span><span style="color: #008000">#</span><span style="color: #008000"> 要进行关联的表名</span>
related_name=None,<span style="color: #008000">#</span><span style="color: #008000"> 在Admin或ModelForm中<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>关联数据时，提供的条件：</span>
<span style="color: #008000">#</span><span style="color: #008000"> 如：</span>
- limit_choices_to={<span style="color: #800000">'</span><span style="color: #800000">nid__gt</span><span style="color: #800000">'</span>: 5<span style="color: #000000">}
</span>- limit_choices_to=<span style="color: #0000ff">lambda</span> : {<span style="color: #800000">'</span><span style="color: #800000">nid__gt</span><span style="color: #800000">'</span>: 5<span style="color: #000000">}
</span><span style="color: #0000ff">from</span> django.db.models <span style="color: #0000ff">import</span><span style="color: #000000"> Q
</span>- limit_choices_to=Q(nid__gt=10<span style="color: #000000">)
</span>- limit_choices_to=Q(nid=8) | Q(nid__gt=10<span style="color: #000000">)
</span>- limit_choices_to=<span style="color: #0000ff">lambda</span> : Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption=<span style="color: #800000">'</span><span style="color: #800000">root</span><span style="color: #800000">'</span><span style="color: #000000">)
symmetrical</span>=None,<span style="color: #008000">#</span><span style="color: #008000"> 仅用于多对多自关联时，symmetrical用于指定内部是否创建反向操作的字段</span>
<span style="color: #008000">#</span><span style="color: #008000"> 做如下操作时，不同的symmetrical会有不同的可选字段</span><span style="color: #000000"> models.BB.objects.filter(...)
</span><span style="color: #008000">#</span><span style="color: #008000"> 可选字段有：code,id,m1</span>
<span style="color: #0000ff">class</span><span style="color: #000000"> BB(models.Model):
code </span>= models.CharField(max_length=12<span style="color: #000000">)
m1 </span>= models.ManyToManyField(<span style="color: #800000">'</span><span style="color: #800000">self</span><span style="color: #800000">'</span>,symmetrical=<span style="color: #000000">True)
</span><span style="color: #008000">#</span><span style="color: #008000"> 可选字段有: bb,code,symmetrical=<span style="color: #000000">False)
through</span>=None,<span style="color: #008000">#</span><span style="color: #008000"> <a href="/tag/zidingyi/" target="_blank" class="keywords">自定义</a>第三张表时，使用字段用于指定关系表</span>
through_fields=None,<span style="color: #008000">#</span><span style="color: #008000"> <a href="/tag/zidingyi/" target="_blank" class="keywords">自定义</a>第三张表时，使用字段用于指定关系表中那些字段做多对多关系表</span>
<span style="color: #0000ff">from</span> django.db <span style="color: #0000ff">import</span><span style="color: #000000"> models
</span><span style="color: #0000ff">class</span><span style="color: #000000"> Person(models.Model):
name </span>= models.CharField(max_length=50<span style="color: #000000">)
</span><span style="color: #0000ff">class</span><span style="color: #000000"> Group(models.Model):
name </span>= models.CharField(max_length=128<span style="color: #000000">)
members </span>=<span style="color: #000000"> models.ManyToManyField(
Person,through</span>=<span style="color: #800000">'</span><span style="color: #800000">Membership</span><span style="color: #800000">'</span><span style="color: #000000">,through_fields</span>=(<span style="color: #800000">'</span><span style="color: #800000">group</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">person</span><span style="color: #800000">'</span><span style="color: #000000">),)
</span><span style="color: #0000ff">class</span><span style="color: #000000"> Membership(models.Model):
group </span>= models.ForeignKey(Group,on_delete=<span style="color: #000000">models.CASCADE)
person </span>= models.ForeignKey(Person,on_delete=<span style="color: #000000">models.CASCADE)
inviter </span>=<span style="color: #000000"> models.ForeignKey(
Person,on_delete</span>=<span style="color: #000000">models.CASCADE,related_name</span>=<span style="color: #800000">"</span><span style="color: #800000">membership_invites</span><span style="color: #800000">"</span><span style="color: #000000">,)
invite_reason </span>= models.CharField(max_length=64<span style="color: #000000">)
db_constraint</span>=True,<span style="color: #008000">#</span><span style="color: #008000"> 是否在<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>中创建外键约束</span>
db_table=None,<span style="color: #008000">#</span><span style="color: #008000"> <a href="/tag/mo/" target="_blank" class="keywords">默</a>认创建第三张表时，<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a>中表的<a href="/tag/mingcheng/" target="_blank" class="keywords">名称</a></span><span style="color: #000000">
多表关系和参数
十，ORM操作
models.Tb1.objects.get(id=123) <span style="color: #008000">#<span style="color: #008000"> 获取单条数据，不存在则报错（不建议）
models.Tb1.objects.all() <span style="color: #008000">#<span style="color: #008000"> 获取全部
models.Tb1.objects.filter(name=<span style="color: #800000">'<span style="color: #800000">seven<span style="color: #800000">') <span style="color: #008000">#<span style="color: #008000"> 获取指定条件的数据
models.Tb1.objects.exclude(name=<span style="color: #800000">'<span style="color: #800000">seven<span style="color: #800000">') <span style="color: #008000">#<span style="color: #008000"> 去除指定条件的数据
<span style="color: #008000">#<span style="color: #008000"> 删<span style="color: #008000">
<span style="color: #008000"> models.Tb1.objects.filter(name='seven').delete() # 删除指定条件的数据
<span style="color: #008000">#<span style="color: #008000"> 改
models.Tb1.objects.filter(name=<span style="color: #800000">'<span style="color: #800000">seven<span style="color: #800000">').update(gender=<span style="color: #800000">'<span style="color: #800000">0<span style="color: #800000">') <span style="color: #008000">#<span style="color: #008000"> 将指定条件的数据更新，均支持 **kwargs
obj = models.Tb1.objects.get(id=1<span style="color: #000000">)
obj.c1 = <span style="color: #800000">'<span style="color: #800000">111<span style="color: #800000">'<span style="color: #000000">
obj.save() <span style="color: #008000">#<span style="color: #008000"> 修改单条数据
获取个数<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(idgt=1) # 获取id大于1的值<span style="color: #008000">#</span><span style="color: #008000"> 大于，小于</span> <span style="color: #008000">#
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(id__gte=1) # 获取id大于等于1的值
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(idlt=10) # 获取id小于10的值
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(id__lte=10) # 获取id小于10的值
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(idlt=10,idgt=1) # 获取id大于1 且 小于10的值<span style="color: #008000">#</span><span style="color: #008000"> in</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(id__in=[11,22,33]) # 获取id等于11、22、33的数据
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.exclude(id__in=[11,33]) # not in<span style="color: #008000">#</span><span style="color: #008000"> isnull</span> <span style="color: #008000">#</span><span style="color: #008000"> Entry.objects.filter(pub_date__isnull=True)</span> <span style="color: #008000">#</span><span style="color: #008000"> contains</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(namecontains="ven")
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(nameicontains="ven") # icontains大小写不敏感
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.exclude(name__icontains="ven")<span style="color: #008000">#</span><span style="color: #008000"> range</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(id__range=[1,2]) # 范围bettwen and
<span style="color: #008000">#</span><span style="color: #008000"> 其他类似</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> startswith，istartswith,endswith,iendswith,
<span style="color: #008000">#</span><span style="color: #008000"> order by</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(name='seven').order_by('id') # asc
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(name='seven').order_by('-id') # desc<span style="color: #008000">#</span><span style="color: #008000"> group by</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> from django.db.models import Count,Min,Max,Sum
<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.filter(c1=1).values('id').annotate(c=Count('num'))
<span style="color: #008000">#<span style="color: #008000"> SELECT "app01_tb1"."id",COUNT("app01_tb1"."num") AS "c" FROM "app01_tb1" WHERE "app01_tb1"."c1" = 1 GROUP BY "app01_tb1"."id"<span style="color: #008000">#</span><span style="color: #008000"> limit 、offset</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> models.Tb1.objects.all()[10:20]
<span style="color: #008000">#</span><span style="color: #008000"> regex正则匹配，iregex 不区分大小写</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Entry.objects.get(titleregex=r'^(An?|The) +')
<span style="color: #008000">#<span style="color: #008000"> Entry.objects.get(titleiregex=r'^(an?|the) +')<span style="color: #008000">#</span><span style="color: #008000"> date</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_date__date=datetime.date(2005,1,1))
<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_datedategt=datetime.date(2005,1))<span style="color: #008000">#</span><span style="color: #008000"> year</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_date__year=2005)
<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_dateyeargte=2005)<span style="color: #008000">#</span><span style="color: #008000"> month</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_date__month=12)
<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_datemonthgte=6)<span style="color: #008000">#</span><span style="color: #008000"> day</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_date__day=3)
<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_datedaygte=3)<span style="color: #008000">#</span><span style="color: #008000"> week_day</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_dateweek_day=2)
<span style="color: #008000">#<span style="color: #008000"> Entry.objects.filter(pub_dateweek_day__gte=2)<span style="color: #008000">#</span><span style="color: #008000"> hour</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timestamphour=23)
<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timehour=5)
<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timestamphourgte=12)<span style="color: #008000">#</span><span style="color: #008000"> minute</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timestampminute=29)
<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timeminute=46)
<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timestampminutegte=29)<span style="color: #008000">#</span><span style="color: #008000"> second</span> <span style="color: #008000">#<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timestampsecond=31)
<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timesecond=2)
<span style="color: #008000">#<span style="color: #008000"> Event.objects.filter(timestampsecondgte=31)
arams=None,tables=None,order_by=None,select_params=None)<span style="color: #008000">#
<span style="color: #008000"> select和select_params是一组，where和params是一组，tables用来设置from哪个表<span style="color: #008000"> <span style="color: #008000"> Entry.objects.extra(select={'new_id': "select col from sometable where othercol > %s"},select_params=(1,))<span style="color: #008000"> <span style="color: #008000"> Entry.objects.extra(where=['headline=%s'],params=['Lennon'])<span style="color: #008000"><span style="color: #008000"> Entry.objects.extra(where=["foo='a' OR bar = 'a'","baz = 'a'"])<span style="color: #008000">
<span style="color: #008000"> Entry.objects.extra(select={'new_id': "select id from tb where id > %s"},),order_by=['-nid'])
<span style="color: #000000">
举个例子：
models.UserInfo.objects.extra(
select={<span style="color: #800000">'<span style="color: #800000">newid<span style="color: #800000">':<span style="color: #800000">'<span style="color: #800000">select count(1) from app01_usertype where id>%s<span style="color: #800000">'<span style="color: #000000">},select_params=[1<span style="color: #000000">,where = [<span style="color: #800000">'<span style="color: #800000">age>%s<span style="color: #800000">'<span style="color: #000000">],params=[18<span style="color: #000000">,order_by=[<span style="color: #800000">'<span style="color: #800000">-age<span style="color: #800000">'<span style="color: #000000">],tables=[<span style="color: #800000">'<span style="color: #800000">app01_usertype<span style="color: #800000">'<span style="color: #000000">]
)
<span style="color: #800000">"""<span style="color: #800000">
select
app01_userinfo.id,(select count(1) from app01_usertype where id>1) as newid
from app01_userinfo,app01_usertype
where
app01_userinfo.age > 18
order by
app01_userinfo.age desc
<span style="color: #800000">"""<span style="color: #008000">#<span style="color: #008000"> 执行原生sql<span style="color: #008000">
<span style="color: #008000"> 更高灵活度的方式执行原生sql语句<span style="color: #008000">
<span style="color: #008000"> from django.db import connection,connections<span style="color: #008000">
<span style="color: #008000"> cursor = connection.cursor() # cursor = connections['default'].cursor()<span style="color: #008000">
<span style="color: #008000"> cursor.execute("""SELECT * from auth_user where id = %s""",[1])<span style="color: #008000">
<span style="color: #008000"> row = cursor.fetchone()
<span style="color: #000000">
高级操作
<span style="color: #0000ff">def
<span style="color: #000000"> all(self)<span style="color: #008000">#<span style="color: #008000"> 获取所有的数据对象
<span style="color: #0000ff">def
filter(self,**<span style="color: #000000">kwargs)<span style="color: #008000">#<span style="color: #008000"> 条件查询
<span style="color: #008000">#<span style="color: #008000"> 条件可以是：参数，字典，Q
<span style="color: #0000ff">def exclude(self,**<span style="color: #000000">kwargs)
<span style="color: #008000">#<span style="color: #008000"> 条件查询
<span style="color: #008000">#<span style="color: #008000"> 条件可以是：参数，字典，Q
<span style="color: #0000ff">def select_related(self,*<span style="color: #000000">fields)
性能相关：表之间进行join连表操作，一次性获取关联的数据。
总结：
</span>1<span style="color: #000000">. select_related主要针一对一和多对一关系进行优化。
</span>2<span style="color: #000000">. select_related使用<a href="/tag/sql/" target="_blank" class="keywords">sql</a>的JOIN语句进行优化，通过减少<a href="/tag/SQLchaxun/" target="_blank" class="keywords">SQL查询</a>的<a href="/tag/cishu/" target="_blank" class="keywords">次数</a>来进行优化、提高<a href="/tag/xingneng/" target="_blank" class="keywords">性能</a>。<span style="color: #0000ff">def prefetch_related(self,*<span style="color: #000000">lookups)
性能相关：多表连表操作时速度会慢，使用其执行多次SQL查询在Python代码中实现连表操作。
总结：
</span>1<span style="color: #000000">. 对于多对多字段（ManyToManyField）和一对多字段，可以使用prefetch_related()来进行优化。
</span>2<span style="color: #000000">. prefetch_related()的优化方式是分别<a href="/tag/chaxun/" target="_blank" class="keywords">查询</a>每个表，然后用Python处理他们之<a href="/tag/jiande/" target="_blank" class="keywords">间的</a>关系。<span style="color: #0000ff">def annotate(self,**<span style="color: #000000">kwargs)
<span style="color: #008000">#<span style="color: #008000"> 用于实现聚合group by查询
<span style="color: #0000ff">from</span> django.db.models <span style="color: #0000ff">import</span><span style="color: #000000"> Count,Avg,Sum
v </span>= models.UserInfo.objects.values(<span style="color: #800000">'</span><span style="color: #800000">u_id</span><span style="color: #800000">'</span>).annotate(uid=Count(<span style="color: #800000">'</span><span style="color: #800000">u_id</span><span style="color: #800000">'</span><span style="color: #000000">))
</span><span style="color: #008000">#</span><span style="color: #008000"> SELECT u_id,COUNT(ui) AS `uid` FROM UserInfo GROUP BY u_id</span><span style="color: #000000">
v = models.UserInfo.objects.values(<span style="color: #800000">'<span style="color: #800000">u_id<span style="color: #800000">').annotate(uid=Count(<span style="color: #800000">'<span style="color: #800000">u_id<span style="color: #800000">')).filter(uid__gt=1<span style="color: #000000">)
<span style="color: #008000">#<span style="color: #008000"> SELECT u_id,COUNT(ui_id) AS uid FROM UserInfo GROUP BY u_id having count(u_id) > 1
<span style="color: #000000">
v = models.UserInfo.objects.values(<span style="color: #800000">'<span style="color: #800000">u_id<span style="color: #800000">').annotate(uid=Count(<span style="color: #800000">'<span style="color: #800000">u_id<span style="color: #800000">',distinct=True)).filter(uid__gt=1<span style="color: #000000">)
<span style="color: #008000">#<span style="color: #008000"> SELECT u_id,COUNT( DISTINCT ui_id) AS uid FROM UserInfo GROUP BY u_id having count(u_id) > 1
<span style="color: #0000ff">def distinct(self,*<span style="color: #000000">field_names)
<span style="color: #008000">#<span style="color: #008000"> 用于distinct去重
models.UserInfo.objects.values(<span style="color: #800000">'<span style="color: #800000">nid<span style="color: #800000">'<span style="color: #000000">).distinct()
<span style="color: #008000">#<span style="color: #008000"> select distinct nid from userinfo
<span style="color: #000000">
注：只有在Postgresql中才能使用distinct进行去重
<span style="color: #0000ff">def order_by(self,*<span style="color: #000000">field_names)
<span style="color: #008000">#<span style="color: #008000"> 用于排序
models.UserInfo.objects.all().order_by(<span style="color: #800000">'<span style="color: #800000">-id<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">age<span style="color: #800000">'<span style="color: #000000">)
<span style="color: #0000ff">def extra(self,select_params=<span style="color: #000000">None)
<span style="color: #008000">#<span style="color: #008000"> 构造额外的查询条件或者映射，如：子查询
<span style="color: #000000">
Entry.objects.extra(select={<span style="color: #800000">'<span style="color: #800000">new_id<span style="color: #800000">': <span style="color: #800000">"<span style="color: #800000">select col from sometable where othercol > %s<span style="color: #800000">"},select_params=(1<span style="color: #000000">,))
Entry.objects.extra(where=[<span style="color: #800000">'<span style="color: #800000">headline=%s<span style="color: #800000">'],params=[<span style="color: #800000">'<span style="color: #800000">Lennon<span style="color: #800000">'<span style="color: #000000">])
Entry.objects.extra(where=[<span style="color: #800000">"<span style="color: #800000">foo='a' OR bar = 'a'<span style="color: #800000">",<span style="color: #800000">"<span style="color: #800000">baz = 'a'<span style="color: #800000">"<span style="color: #000000">])
Entry.objects.extra(select={<span style="color: #800000">'<span style="color: #800000">new_id<span style="color: #800000">': <span style="color: #800000">"<span style="color: #800000">select id from tb where id > %s<span style="color: #800000">"},order_by=[<span style="color: #800000">'<span style="color: #800000">-nid<span style="color: #800000">'<span style="color: #000000">])
<span style="color: #0000ff">def<span style="color: #000000"> reverse(self):
<span style="color: #008000">#<span style="color: #008000"> 倒序
models.UserInfo.objects.all().order_by(<span style="color: #800000">'<span style="color: #800000">-nid<span style="color: #800000">'<span style="color: #000000">).reverse()
<span style="color: #008000">#<span style="color: #008000"> 注：如果存在order_by，reverse则是倒序，如果多个排序则一一倒序
<span style="color: #0000ff">def defer(self,*<span style="color: #000000">fields):
models.UserInfo.objects.defer(<span style="color: #800000">'<span style="color: #800000">username<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">id<span style="color: #800000">'<span style="color: #000000">)
或
models.UserInfo.objects.filter(...).defer(<span style="color: #800000">'<span style="color: #800000">username<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">id<span style="color: #800000">'<span style="color: #000000">)
<span style="color: #008000">#<span style="color: #008000">映射中排除某列数据
<span style="color: #0000ff">def only(self,*<span style="color: #000000">fields):
<span style="color: #008000">#<span style="color: #008000">仅取某个表中的数据
models.UserInfo.objects.only(<span style="color: #800000">'<span style="color: #800000">username<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">id<span style="color: #800000">'<span style="color: #000000">)
或
models.UserInfo.objects.filter(...).only(<span style="color: #800000">'<span style="color: #800000">username<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">id<span style="color: #800000">'<span style="color: #000000">)
<span style="color: #0000ff">def<span style="color: #000000"> using(self,alias):
指定使用的数据库，参数为别名（setting中的设置）
<span style="color: #008000">#<span style="color: #008000">#################################################<span style="color: #008000">
<span style="color: #008000"> PUBLIC METHODS THAT RETURN A QUERYSET SUBCLASS #<span style="color: #008000">
<span style="color: #008000">#################################################
<span style="color: #0000ff">def raw(self,raw_query,translations=None,using=<span style="color: #000000">None):
<span style="color: #008000">#<span style="color: #008000"> 执行原生sql
models.UserInfo.objects.raw(<span style="color: #800000">'<span style="color: #800000">select * from userinfo<span style="color: #800000">'<span style="color: #000000">)
</span><span style="color: #008000">#</span><span style="color: #008000"> 如果<a href="/tag/sql/" target="_blank" class="keywords">sql</a>是其他表时，必须将名字设置为当前UserInfo对象的主键列名</span>
models.UserInfo.objects.raw(<span style="color: #800000">'</span><span style="color: #800000">select id as nid from 其他表</span><span style="color: #800000">'</span><span style="color: #000000">)
</span><span style="color: #008000">#</span><span style="color: #008000"> 为原生<a href="/tag/sql/" target="_blank" class="keywords">sql</a>设置参数</span>
models.UserInfo.objects.raw(<span style="color: #800000">'</span><span style="color: #800000">select id as nid from userinfo where nid><a href="/tag/s/" target="_blank" class="keywords">%s</a></span><span style="color: #800000">'</span>,p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>ms=[12<span style="color: #000000">,])
</span><span style="color: #008000">#</span><span style="color: #008000"> 将<a href="/tag/huoqu/" target="_blank" class="keywords">获取</a>的到列名转换为指定列名</span>
name_map = {<span style="color: #800000">'</span><span style="color: #800000">f<a href="/tag/irs/" target="_blank" class="keywords">irs</a>t</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">f<a href="/tag/irs/" target="_blank" class="keywords">irs</a>t_name</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">last</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">last_name</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">bd</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">birth_date</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">pk</span><span style="color: #800000">'</span>: <span style="color: #800000">'</span><span style="color: #800000">id</span><span style="color: #800000">'</span><span style="color: #000000">}
Person.objects.raw(</span><span style="color: #800000">'</span><span style="color: #800000">SELECT * FROM some_other_table</span><span style="color: #800000">'</span>,translations=<span style="color: #000000">name_map)
</span><span style="color: #008000">#</span><span style="color: #008000"> 指定<a href="/tag/shujuku/" target="_blank" class="keywords">数据库</a></span>
models.UserInfo.objects.raw(<span style="color: #800000">'</span><span style="color: #800000">select * from userinfo</span><span style="color: #800000">'</span>,using=<span style="color: #800000">"</span><span style="color: #800000">default</span><span style="color: #800000">"</span><span style="color: #000000">)
</span><span style="color: #008000">#</span><span style="color: #008000">################## 原生<a href="/tag/sql/" target="_blank" class="keywords">sql</a> ###################</span>
<span style="color: #0000ff">from</span> django.db <span style="color: #0000ff">import</span><span style="color: #000000"> connection,connections
cursor </span>= connection.cursor() <span style="color: #008000">#</span><span style="color: #008000"> cursor = connections['default'].cursor()</span>
cursor.execute(<span style="color: #800000">"""</span><span style="color: #800000">SELECT * from auth_user where id = <a href="/tag/s/" target="_blank" class="keywords">%s</a></span><span style="color: #800000">"""</span>,[1<span style="color: #000000">])
row </span>= cursor.fetchone() <span style="color: #008000">#</span><span style="color: #008000"> fetchall()/fetchmany(..)</span><span style="color: #0000ff">def values(self,*<span style="color: #000000">fields):
<span style="color: #008000">#<span style="color: #008000"> 获取每行数据为字典格式
<span style="color: #0000ff">def values_list(self,*fields,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 获取每行数据为元祖
<span style="color: #0000ff">def dates(self,field_name,kind,order=<span style="color: #800000">'<span style="color: #800000">ASC<span style="color: #800000">'<span style="color: #000000">):
<span style="color: #008000">#<span style="color: #008000"> 根据时间进行某一部分进行去重查找并截取指定内容
<span style="color: #008000">#<span style="color: #008000"> kind只能是："year"（年）,"month"（年-月）,"day"（年-月-日）
<span style="color: #008000">#<span style="color: #008000"> order只能是："ASC" "DESC"
<span style="color: #008000">#<span style="color: #008000"> 并获取转换后的时间
- year : 年-01-01
- month: 年-月-01
- day : 年-月-<span style="color: #000000">日
models.DatePlus.objects.dates(</span><span style="color: #800000">'</span><span style="color: #800000">ctime</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">day</span><span style="color: #800000">'</span>,<span style="color: #800000">'</span><span style="color: #800000">DESC</span><span style="color: #800000">'</span><span style="color: #000000">)<span style="color: #0000ff">def datetimes(self,order=<span style="color: #800000">'<span style="color: #800000">ASC<span style="color: #800000">',tzinfo=<span style="color: #000000">None):
<span style="color: #008000">#<span style="color: #008000"> 根据时间进行某一部分进行去重查找并截取指定内容，将时间转换为指定时区时间
<span style="color: #008000">#<span style="color: #008000"> kind只能是 "year","month","day","hour","minute","second"
<span style="color: #008000">#<span style="color: #008000"> order只能是："ASC" "DESC"
<span style="color: #008000">#<span style="color: #008000"> tzinfo时区对象
models.DDD.objects.datetimes(<span style="color: #800000">'<span style="color: #800000">ctime<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">hour<span style="color: #800000">',tzinfo=<span style="color: #000000">pytz.UTC)
models.DDD.objects.datetimes(<span style="color: #800000">'<span style="color: #800000">ctime<span style="color: #800000">',tzinfo=pytz.timezone(<span style="color: #800000">'<span style="color: #800000">Asia/Shanghai<span style="color: #800000">'<span style="color: #000000">))
</span><span style="color: #800000">"""</span><span style="color: #800000">
pip3 install pytz
import pytz
pytz.all_timezo<a href="/tag/nes/" target="_blank" class="keywords">nes</a>
pytz.timezone(‘Asia/Shanghai’)
</span><span style="color: #800000">"""</span><span style="color: #0000ff">def<span style="color: #000000"> none(self):
<span style="color: #008000">#<span style="color: #008000"> 空QuerySet对象
<span style="color: #008000">#<span style="color: #008000">###################################<span style="color: #008000">
<span style="color: #008000"> METHODS THAT DO DATABASE QUERIES #<span style="color: #008000">
<span style="color: #008000">###################################
<span style="color: #0000ff">def aggregate(self,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 聚合函数，获取字典类型聚合结果
<span style="color: #0000ff">from django.db.models <span style="color: #0000ff">import<span style="color: #000000"> Count,Sum
result = models.UserInfo.objects.aggregate(k=Count(<span style="color: #800000">'<span style="color: #800000">u_id<span style="color: #800000">',distinct=True),n=Count(<span style="color: #800000">'<span style="color: #800000">nid<span style="color: #800000">'<span style="color: #000000">))
===> {<span style="color: #800000">'<span style="color: #800000">k<span style="color: #800000">': 3,<span style="color: #800000">'<span style="color: #800000">n<span style="color: #800000">': 4<span style="color: #000000">}
<span style="color: #0000ff">def<span style="color: #000000"> count(self):
<span style="color: #008000">#<span style="color: #008000"> 获取个数
<span style="color: #0000ff">def get(self,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 获取单个对象
<span style="color: #0000ff">def create(self,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 创建对象
<span style="color: #0000ff">def bulk_create(self,objs,batch_size=<span style="color: #000000">None):
<span style="color: #008000">#<span style="color: #008000"> 批量插入
<span style="color: #008000">#<span style="color: #008000"> batch_size表示一次插入的个数
objs =<span style="color: #000000"> [
models.DDD(name=<span style="color: #800000">'<span style="color: #800000">r11<span style="color: #800000">'<span style="color: #000000">),models.DDD(name=<span style="color: #800000">'<span style="color: #800000">r22<span style="color: #800000">'<span style="color: #000000">)
]
models.DDD.objects.bulk_create(objs,10<span style="color: #000000">)
<span style="color: #0000ff">def get_or_create(self,defaults=None,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 如果存在，则获取，否则，创建
<span style="color: #008000">#<span style="color: #008000"> defaults 指定创建时，其他字段的值
obj,created = models.UserInfo.objects.get_or_create(username=<span style="color: #800000">'<span style="color: #800000">root1<span style="color: #800000">',defaults={<span style="color: #800000">'<span style="color: #800000">email<span style="color: #800000">': <span style="color: #800000">'<span style="color: #800000">1111111<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">u_id<span style="color: #800000">': 2,<span style="color: #800000">'<span style="color: #800000">t_id<span style="color: #800000">': 2<span style="color: #000000">})
<span style="color: #0000ff">def update_or_create(self,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 如果存在，则更新，否则，创建
<span style="color: #008000">#<span style="color: #008000"> defaults 指定创建时或更新时的其他字段
obj,created = models.UserInfo.objects.update_or_create(username=<span style="color: #800000">'<span style="color: #800000">root1<span style="color: #800000">',<span style="color: #800000">'<span style="color: #800000">t_id<span style="color: #800000">': 1<span style="color: #000000">})
<span style="color: #0000ff">def<span style="color: #000000"> first(self):
<span style="color: #008000">#<span style="color: #008000"> 获取第一个
<span style="color: #0000ff">def<span style="color: #000000"> last(self):
<span style="color: #008000">#<span style="color: #008000"> 获取最后一个
<span style="color: #0000ff">def in_bulk(self,id_list=<span style="color: #000000">None):
<span style="color: #008000">#<span style="color: #008000"> 根据主键ID进行查找
id_list = [11,21,31<span style="color: #000000">]
models.DDD.objects.in_bulk(id_list)
<span style="color: #0000ff">def<span style="color: #000000"> delete(self):
<span style="color: #008000">#<span style="color: #008000"> 删除
<span style="color: #0000ff">def update(self,**<span style="color: #000000">kwargs):
<span style="color: #008000">#<span style="color: #008000"> 更新
<span style="color: #0000ff">def<span style="color: #000000"> exists(self):
<span style="color: #008000">#<span style="color: #008000"> 是否有结果
<span style="color: #000000">
其他操作
QuerySet方法大全
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 [email protected] 举报，一经查实，本站将立刻删除。
