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【Django】--Model字段

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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_112233\d+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()



















   

















          









      














































    



















     



























































 

【Django】--Model字段

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原文地址:http://www.cnblogs.com/bk770466199/p/6220568.html

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