标签:upm new address osi color 继承 text reg class
djiango在数据库这方式自己实现了orm(object relationship mapping 对象关系模型映射)、这个主要是用到python 元类这一
项python中的高级技术来实现的。
class ModelBase(type): def __new__(cls,name,bases,attrs): # ..... pass pass class Model(metaclass=ModelBase): pass # 在这之后所有的用户自定义模型都继承自Model类 class Person(Model): name=CharField(max_length=8)
类就对应到了数据库中的一张表、而类的的属性就对应到了表中的列;如这里的Person类就对应到了person表,name属性就对应到了name列
上面例子中name属性的数据类型是CharField类型、这种类型与数据库端的char类型对应;在django中所以的列类型都继承自Field类型
class Feild(RegisterLookupMixin): pass class AutoField(Field): class BigAutoField(AutoField): class BooleanField(Field): class CharField(Field): class CommaSeparatedIntegerField(CharField): class DateTimeCheckMixin: class DateField(DateTimeCheckMixin, Field): class DateTimeField(DateField): class DecimalField(Field): class DurationField(Field): class EmailField(CharField): class FilePathField(Field): class FloatField(Field): class IntegerField(Field): class BigIntegerField(IntegerField): class IPAddressField(Field): class GenericIPAddressField(Field): class NullBooleanField(Field): class PositiveIntegerRelDbTypeMixin: class PositiveIntegerField(PositiveIntegerRelDbTypeMixin, IntegerField): class PositiveSmallIntegerField(PositiveIntegerRelDbTypeMixin, IntegerField): class SlugField(CharField): class SmallIntegerField(IntegerField): class TextField(Field): class TimeField(DateTimeCheckMixin, Field): class URLField(CharField): class BinaryField(Field): class UUIDField(Field):
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django源码分析---- Model类型&Field类型
标签:upm new address osi color 继承 text reg class
原文地址:http://www.cnblogs.com/JiangLe/p/6722003.html