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  • 【Django】--Model字段

    参考地址:http://www.cnblogs.com/wupeiqi/articles/6216618.html

    所有字段
      AutoField(Field)
        --int自增列,必须填入参数primary_key=True
      BigAutoField(AutoField)
        --bigint自增列,必须填入参数primary_key=True
        注意:当model中没有自增列,则自动会创建一个列名为id的列
          
    from django.db import models
        class UserInfo(models.Model):
          #自动创建一个列名为id的且为自增的整数列
          username = models.CharField(max_length=32)
        class Group(modes.Model):
          #自定义自增列
          nid = models.AutoField(primary_key = True)
          name = models.CharField(max_length=32)
      SmallIntegerField(IntegerField):
        --小整数 -32768 ~ 32767
      PositiveSmallIntegerField(PositiveIntegerRelDbTypeMixin,IntegerField)
        --正小整数 0 ~ 32767
      PositiveSmallIntegerField(PositiveIntegerRelDbTypeMixin,IntergerField)
        --正小整数 0 ~ 32767
      IntegerField(Field)
        --整数列(有符号的) -2147483648 ~ 2147483647
      PositiveIntegerField(PositiveIntegerRelDbTypeMixin,IntegerField)
        --正整数 0 ~ 2147483647
      BigINtegerField(IntegerField):
        --长整型(有符号的) -9223372036854775808 ~ 9223372036854775807
      
      自定义无符号整数字段

        class UnsignedIntegerFIeld(models.IntegerField):
          def db_type(self,connection):
            return "integer UNSIGNED"

        PS:返回值为字段在数据库中的属性,Django字段默认的值为:

          "AutoField" : "integer AUTO_INCREMENT",
          "BigAutoField": "bigint AUTO_INCREMENT",
          "BinaryField":"longblob",
          "BooleanField":"bool",
          "CharField" : "varchar(%(max_length)s)",
          "CommaSeparatedIntegerField" : "varchar(%(max_length)s)",
          "DateField": "date",
          "DateTimeField":"datetime",
          "DecimalField":"numeric(%(max_digits)s,%(decimal_places)s)",
          "DurationField":"bigint",
          "FileField":"varchar(%(max_length)s)",
          "FilePathField":"varchar(%(max_length)s)",
          "FloatField":"double precision",
          "IntegerField":"integer",
          "BigIntegerField":"bigint",
          "IPAddressField":"char(15)”,
          "GenericIPAddressField":"char(39)",
          "NullBooleanField":"bool",
          "OneToOneField":"integer",
          "PositiveSmallIntegerField":"smallint UNSIGNED",
          "SlugField":"varchar(%(max_length)s)",
          "SmallIntegerField":"smallint",
          "TextField":"longtext",
          "TimeField":"time",
          "UUIDField":"char(32)",

      BooleanField(Field)
         --布尔值类型
      NullBooleanField(Field):
         --可以为空的布尔值
      CharField(Field)
         --字符类型
         --必须提供max_length参数,max_length表示字符长度

      TextField(Field)
         --文本类型

      EmailField(CharField):
        --字符串类型,Django Admin以及ModelForm中提供验证机制

      IPAddressField(Field)
        --字符串类型,Django Admin以及ModelForm中提供验证 IPV4 机制

      GenericIPAddressField(Field)
        
        --字符串类型,Django Admin以及ModelForm中提供验证 IPV4 和 IPV6
        --参数:
          protocol,用于指定IPV4或IPV6,"both","ipv4","ipv6"
    解析为192.0.2.1,开启此功能,需要protocol="both"
      URLField(CharField)
        --字符串类型,Django Admin以及ModelForm中提供验证 URL
      SlugField(CharField)
        --字符串类型,Django Admin 以及ModelForm中提供验证支持字母,数字,下划线,连接符(减号)
      CommaSeparatedIntegerField(CharField)
        --字符串类型,格式必须为逗号分割的数字

      UUIDField(Field)
        --字符串类型,Django Admin以及ModelForm中提供对UUID格式的验证

      FilePathField(Field)
        --字符串,Django Admin以及MOdelForm中提供读取文件夹下文件的功能
        --参数:
          path, 文件夹路径
          match=None, 正则匹配
          recursive = False, 递归下面的文件夹
          allow_files = True, 允许文件
          allow_folders =False 允许文件夹

      FileField(Field)
        --字符串,路径保存在数据库,文件上传到指定目录
        --参数:
          upload_to = "" 上传文件的保存路径
          storage = None 存储组件,默认

    django.core.files.storage.FileSystemStorage
      ImageField(FileField)
        --字符串,路径保存在数据库,文件上传到指定目录
        --参数:
          upload_to = "" 上传文件的保存路径
          storage = None 存储组件,默认
    django.core.files.storage.FileSystemStorage
        width_field=None,上传图片的高度保存到数据库字段名(字符串)
        height_field = None, 上传图片的宽度保存的数据库字段名(字符串)
    DateTimeField(DateField)
      --日期+时间格式 YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ]
    DateField(DateTimeCheckMixin,Field)
      --日期格式 YYYY-MM-DD
    TimeField(DateTimeCheckMixin,Field)
      --时间格式 HH:MM[:SS[.uuuuuu]]
    DurationField(Field)
      --长整数,时间间隔,数据库中按照bigint存储,ORM中获取的值为


    datetime.timedelta类型
      FloatField(Field)
        --浮点型
      DecimalField(Field)
        --10进制小数
        --参数:
          max_digits, 小数总长度
          decimal_places,小数位长度
      BinaryField

    参数:
      null 数据库中字段是否可以为空
      db_column 数据库中字段的列名
      db_tablespace
      default 数据库中字段的默认值
      primary_key 数据库中字段
      db_index 数据库中字段是否可以建立索引
      unique     数据库中字段是否可以建立唯一索引
      unique_for_date 数据库中字段【日期】部分是否可以建立唯一索引
      unique_for_month 数据库中字段【月】部分是否可以建立唯一索引
      unique_for_year 数据库中字段【年】部分是否可以建立唯一索引

      verbose_name Admin中显示的字段名称
      blank Admin中是否允许用户输入为空
      editable Admin中是否可以编辑
      help_text Admin中该字段的提示信息
      choices Admin中显示选择框的内容,用不变动的数据放在内存中从而避免跨表操作
      
      如:gf = models.IntegerField(choices=[(0,"杂杂"),(1,"啊啊“),],default=1)
        error_messages 自定义错误信息(字典类型),从而定制想要显示的错误信息;
        字典键:null,blank,invalid,invalid_choice,unique,and unique_for_date
          如:{"null":"不能为空","invalid":"格式错误"}
      validators 自定义错误验证(列表类型),从而定制想要的验证规则
              from django.core.validators import egexValidator
              from django.core.validators import mailValidator,
                URLValidator,DecimalValidator,
          MaxLengthValidator,MinLengthValidator,MaxValidator,MinValidator如:
            test = models.CharField(
              max_length = 32,
              error_messages = {
              "c1":"优先错信息1",
              ”c2“:"优先错信息2",
              "c3":"优先错信息3",
              },
              validators = [
                RegexValidator(regex="root_d+",message="错误了,code="c1"),
                RegexValidator(regex="root_112233d+messae="又错误了",code="c2"),
                EmailValidator(message="又错误了,code="c3"),]
            )

    元信息
      
      class UserInfo(models.Model):
        nid = models.AutoField(primary_key=True)
        username = models.CharField(max_length=32)
        class Meta;
          #数据库中生成的表名称 默认app名称 + 下划线 +类名
          db_table = "table_name"
          #联合索引
          index_together = [
          ("pub_date","deadline"),
          ]
          
          #联合唯一索引
          unique_together = (("driver","restaurant"),) 

          #admin中显示的表名称
             verbose_name

          #verbose_name 加s
          
          verbose_name_plural

      更多:https://docs.djangoproject.com/en/1.10/ref/models/options/
      注:
        1.触发Model中的验证和错误提示有两种方式:
          a. Django Admin中的错误信息会优先根据Admiin内部的ModelForm错误信息提示,如果都成功,才来检查Model的字段并显示指定错误信息

          b.调用Model对象的 clean_fields 方法,如:
        
           # models.py
                class UserInfo(models.Model):
                    nid = models.AutoField(primary_key=True)
                    username = models.CharField(max_length=32)

                    email = models.EmailField(error_messages={'invalid': '格式错了.'})

                # views.py
                def index(request):
                    obj = models.UserInfo(username='11234', email='uu')
                    try:
                        print(obj.clean_fields())
                    except Exception as e:
                        print(e)
                    return HttpResponse('ok')

               # Model的clean方法是一个钩子,可用于定制操作,如:上述的异常处理。

        2.Admin中修改错误提示
          
           # admin.py
            from django.contrib import admin
            from model_club import models
            from django import forms


            class UserInfoForm(forms.ModelForm):
                username = forms.CharField(error_messages={'required': '用户名不能为空.'})
                email = forms.EmailField(error_messages={'invalid': '邮箱格式错误.'})
                age = forms.IntegerField(initial=1, error_messages={'required': '请输入数值.', 'invalid': '年龄必须为数值.'})

                class Meta:
                    model = models.UserInfo
                    # fields = ('username',)
                    fields = "__all__"


            class UserInfoAdmin(admin.ModelAdmin):
                form = UserInfoForm

            admin.site.register(models.UserInfo, UserInfoAdmin)


    四、多表关系
        ForeignKey(ForeignObject) # ForeignObject(RelatedField)
            to,                         # 要进行关联的表名
            to_field=None,              # 要关联的表中的字段名称
            on_delete=None,             # 当删除关联表中的数据时,当前表与其关联的行的行为
                                            - models.CASCADE,删除关联数据,与之关联也删除
                                            - models.DO_NOTHING,删除关联数据,引发错误IntegrityError
                                            - models.PROTECT,删除关联数据,引发错误ProtectedError
                                            - models.SET_NULL,删除关联数据,与之关联的值设置为null(前提FK字段需要设置为可空)
                                            - models.SET_DEFAULT,删除关联数据,与之关联的值设置为默认值(前提FK字段需要设置默认值)
                                            - models.SET,删除关联数据,
                                                          a. 与之关联的值设置为指定值,设置:models.SET(值)
                                                          b. 与之关联的值设置为可执行对象的返回值,设置:models.SET(可执行对象)

                                                            def func():
                                                                return 10

                                                            class MyModel(models.Model):
                                                                user = models.ForeignKey(
                                                                    to="User",
                                                                    to_field="id"
                                                                    on_delete=models.SET(func),)
            related_name=None,          # 反向操作时,使用的字段名,用于代替 【表名_set】 如: obj.表名_set.all()
            related_query_name=None,    # 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')
            limit_choices_to=None,      # 在Admin或ModelForm中显示关联数据时,提供的条件:
                                        # 如:
                                                - limit_choices_to={'nid__gt': 5}
                                                - limit_choices_to=lambda : {'nid__gt': 5}

                                                from django.db.models import Q
                                                - limit_choices_to=Q(nid__gt=10)
                                                - limit_choices_to=Q(nid=8) | Q(nid__gt=10)
                                                - limit_choices_to=lambda : Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption='root')
            db_constraint=True          # 是否在数据库中创建外键约束
            parent_link=False           # 在Admin中是否显示关联数据


        OneToOneField(ForeignKey)
            to,                         # 要进行关联的表名
            to_field=None               # 要关联的表中的字段名称
            on_delete=None,             # 当删除关联表中的数据时,当前表与其关联的行的行为

                                        ###### 对于一对一 ######
                                        # 1. 一对一其实就是 一对多 + 唯一索引
                                        # 2.当两个类之间有继承关系时,默认会创建一个一对一字段
                                        # 如下会在A表中额外增加一个c_ptr_id列且唯一:
                                                class C(models.Model):
                                                    nid = models.AutoField(primary_key=True)
                                                    part = models.CharField(max_length=12)

                                                class A(C):
                                                    id = models.AutoField(primary_key=True)
                                                    code = models.CharField(max_length=1)

        ManyToManyField(RelatedField)
            to,                         # 要进行关联的表名
            related_name=None,          # 反向操作时,使用的字段名,用于代替 【表名_set】 如: obj.表名_set.all()
            related_query_name=None,    # 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')
            limit_choices_to=None,      # 在Admin或ModelForm中显示关联数据时,提供的条件:
                                        # 如:
                                                - limit_choices_to={'nid__gt': 5}
                                                - limit_choices_to=lambda : {'nid__gt': 5}

                                                from django.db.models import Q
                                                - limit_choices_to=Q(nid__gt=10)
                                                - limit_choices_to=Q(nid=8) | Q(nid__gt=10)
                                                - limit_choices_to=lambda : Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption='root')
            symmetrical=None,           # 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
                                        # 做如下操作时,不同的symmetrical会有不同的可选字段
                                            models.BB.objects.filter(...)

                                            # 可选字段有:code, id, m1
                                                class BB(models.Model):

                                                code = models.CharField(max_length=12)
                                                m1 = models.ManyToManyField('self',symmetrical=True)

                                            # 可选字段有: bb, code, id, m1
                                                class BB(models.Model):

                                                code = models.CharField(max_length=12)
                                                m1 = models.ManyToManyField('self',symmetrical=False)

            through=None,               # 自定义第三张表时,使用字段用于指定关系表
            through_fields=None,        # 自定义第三张表时,使用字段用于指定关系表中那些字段做多对多关系表
                                            from django.db import models

                                            class Person(models.Model):
                                                name = models.CharField(max_length=50)

                                            class Group(models.Model):
                                                name = models.CharField(max_length=128)
                                                members = models.ManyToManyField(
                                                    Person,
                                                    through='Membership',
                                                    through_fields=('group', 'person'),
                                                )

                                            class Membership(models.Model):
                                                group = models.ForeignKey(Group, on_delete=models.CASCADE)
                                                person = models.ForeignKey(Person, on_delete=models.CASCADE)
                                                inviter = models.ForeignKey(
                                                    Person,
                                                    on_delete=models.CASCADE,
                                                    related_name="membership_invites",
                                                )
                                                invite_reason = models.CharField(max_length=64)
            db_constraint=True,         # 是否在数据库中创建外键约束
            db_table=None,              # 默认创建第三张表时,数据库中表的名称

        练习:使用ForeignKey 、ManyToManyField、OneToOneField创建表

    五、操作
        基本操作:
            # 增
            #
            # models.Tb1.objects.create(c1='xx', c2='oo')  增加一条数据,可以接受字典类型数据 **kwargs

            # obj = models.Tb1(c1='xx', c2='oo')
            # obj.save()

            # 查
            #
            # models.Tb1.objects.get(id=123)         # 获取单条数据,不存在则报错(不建议)
            # models.Tb1.objects.all()               # 获取全部
            # models.Tb1.objects.filter(name='seven') # 获取指定条件的数据
            # models.Tb1.objects.exclude(name='seven') # 获取指定条件的数据

            # 删
            #
            # models.Tb1.objects.filter(name='seven').delete() # 删除指定条件的数据

            # 改
            # models.Tb1.objects.filter(name='seven').update(gender='0')  # 将指定条件的数据更新,均支持 **kwargs
            # obj = models.Tb1.objects.get(id=1)
            # obj.c1 = '111'
            # obj.save()                                                 # 修改单条数据

        进阶操作:
            # 获取个数
            #
            # models.Tb1.objects.filter(name='seven').count()

            # 大于,小于
            #
            # models.Tb1.objects.filter(id__gt=1)              # 获取id大于1的值
            # models.Tb1.objects.filter(id__gte=1)              # 获取id大于等于1的值
            # models.Tb1.objects.filter(id__lt=10)             # 获取id小于10的值
            # models.Tb1.objects.filter(id__lte=10)             # 获取id小于10的值
            # models.Tb1.objects.filter(id__lt=10, id__gt=1)   # 获取id大于1 且 小于10的值

            # in
            #
            # models.Tb1.objects.filter(id__in=[11, 22, 33])   # 获取id等于11、22、33的数据
            # models.Tb1.objects.exclude(id__in=[11, 22, 33])  # not in

            # isnull
            # Entry.objects.filter(pub_date__isnull=True)

            # contains
            #
            # models.Tb1.objects.filter(name__contains="ven")
            # models.Tb1.objects.filter(name__icontains="ven") # icontains大小写不敏感
            # models.Tb1.objects.exclude(name__icontains="ven")

            # range
            #
            # models.Tb1.objects.filter(id__range=[1, 2])   # 范围bettwen and

            # 其他类似
            #
            # startswith,istartswith, endswith, iendswith,

            # order by
            #
            # models.Tb1.objects.filter(name='seven').order_by('id')    # asc
            # models.Tb1.objects.filter(name='seven').order_by('-id')   # desc

            # group by
            #
            # from django.db.models import Count, Min, Max, Sum
            # models.Tb1.objects.filter(c1=1).values('id').annotate(c=Count('num'))
            # SELECT "app01_tb1"."id", COUNT("app01_tb1"."num") AS "c" FROM "app01_tb1" WHERE "app01_tb1"."c1" = 1 GROUP BY "app01_tb1"."id"

            # limit 、offset
            #
            # models.Tb1.objects.all()[10:20]

            # regex正则匹配,iregex 不区分大小写
            #
            # Entry.objects.get(title__regex=r'^(An?|The) +')
            # Entry.objects.get(title__iregex=r'^(an?|the) +')

            # date
            #
            # Entry.objects.filter(pub_date__date=datetime.date(2005, 1, 1))
            # Entry.objects.filter(pub_date__date__gt=datetime.date(2005, 1, 1))

            # year
            #
            # Entry.objects.filter(pub_date__year=2005)
            # Entry.objects.filter(pub_date__year__gte=2005)

            # month
            #
            # Entry.objects.filter(pub_date__month=12)
            # Entry.objects.filter(pub_date__month__gte=6)

            # day
            #
            # Entry.objects.filter(pub_date__day=3)
            # Entry.objects.filter(pub_date__day__gte=3)

            # week_day
            #
            # Entry.objects.filter(pub_date__week_day=2)
            # Entry.objects.filter(pub_date__week_day__gte=2)

            # hour
            #
            # Event.objects.filter(timestamp__hour=23)
            # Event.objects.filter(time__hour=5)
            # Event.objects.filter(timestamp__hour__gte=12)

            # minute
            #
            # Event.objects.filter(timestamp__minute=29)
            # Event.objects.filter(time__minute=46)
            # Event.objects.filter(timestamp__minute__gte=29)

            # second
            #
            # Event.objects.filter(timestamp__second=31)
            # Event.objects.filter(time__second=2)
            # Event.objects.filter(timestamp__second__gte=31)

        其他操作:
            # extra
            #
            # extra(self, select=None, where=None, params=None, tables=None, order_by=None, select_params=None)
            #    Entry.objects.extra(select={'new_id': "select col from sometable where othercol > %s"}, select_params=(1,))
            #    Entry.objects.extra(where=['headline=%s'], params=['Lennon'])
            #    Entry.objects.extra(where=["foo='a' OR bar = 'a'", "baz = 'a'"])
            #    Entry.objects.extra(select={'new_id': "select id from tb where id > %s"}, select_params=(1,), order_by=['-nid'])

            # F
            #
            # from django.db.models import F
            # models.Tb1.objects.update(num=F('num')+1)


            # Q
            #
            # 方式一:
            # Q(nid__gt=10)
            # Q(nid=8) | Q(nid__gt=10)
            # Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption='root')

            # 方式二:
            # con = Q()
            # q1 = Q()
            # q1.connector = 'OR'
            # q1.children.append(('id', 1))
            # q1.children.append(('id', 10))
            # q1.children.append(('id', 9))
            # q2 = Q()
            # q2.connector = 'OR'
            # q2.children.append(('c1', 1))
            # q2.children.append(('c1', 10))
            # q2.children.append(('c1', 9))
            # con.add(q1, 'AND')
            # con.add(q2, 'AND')
            #
            # models.Tb1.objects.filter(con)


            # 执行原生SQL
            #
            # from django.db import connection, connections
            # cursor = connection.cursor()  # cursor = connections['default'].cursor()
            # cursor.execute("""SELECT * from auth_user where id = %s""", [1])
            # row = cursor.fetchone()



















       

















              









          














































        



















         



























































    人生短短数十载,经不起几次重头再来
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  • 原文地址:https://www.cnblogs.com/bk770466199/p/6220568.html
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