由一个模型拿它的名字、app的名字、字段对象以及字段对象中的属性

publish表数据

  

app01/models.py 

from django.db import modelsclass Publish(models.Model):
    nid = models.AutoField(primary_key=True)
    name=models.CharField( max_length=32)
    city=models.CharField( max_length=32)
    email=models.EmailField()

    def __str__(self):
        return self.name

class Book(models.Model):

    nid = models.AutoField(primary_key=True,verbose_name=" 编号")  #定义在admin中显示中文名称“编号”
    title = models.CharField( max_length=32,verbose_name="书籍名称")
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)

    # 与Publish建立一对多的关系,外键字段建立在多的一方
    publish=models.ForeignKey(to="Publish",to_field="nid",on_delete=models.CASCADE)
    # 与Author表建立多对多的关系,ManyToManyField可以建在两个模型中的任意一个，自动创建第三张表
    authors=models.ManyToManyField(to='Author',)

    def __str__(self):
        return self.title 

app01/views.py 

from django.shortcuts import render,HttpResponse

from app01.models import *

def test(request):
    # 由一个模型拿它的名字、app的名字、字段对象以及字段对象中的属性
    #拿模型名称
    model_name = Book._meta.model_name
    print(model_name,type(model_name))     # book <class 'str'>
    #拿模型的app名称
    app_label = Book._meta.app_label
    print(app_label,type(app_label))       # app01 <class 'str'>
    # 拿模型的字段对象
    title = Book._meta.get_field("title")
    print(title,type(title))               # app01.Book.title    <class 'django.db.models.fields.CharField'>

    max_length = title.max_length
    print(max_length,type(max_length))     # 32 <class 'int'>
    # 获取字段中定义的名称（可中文或英文）
    var = title.verbose_name
    print(var,type(var))                   # 书籍名称 <class 'str'>

    #--------------------------------------------------------------------------------------------
    #由字段的字符串名称“publish”取字段对象、该字段的模型表名称、该字段相关联的模型、
    # 以及该字段相关联模型表的所有数据

    #取字段对象
    publish = Book._meta.get_field("publish")
    print(publish,type(publish))
    #app01.Book.publish <class 'django.db.models.fields.related.ForeignKey'>

    #取该字段模型表
    publish_model_name=publish.rel
    print(publish_model_name,type(publish_model_name))
    #<ManyToOneRel: app01.book> <class 'django.db.models.fields.reverse_related.ManyToOneRel'>

    # 取该字段相关联模型表
    publish_relate_model_name=publish.rel.to
    print(publish_relate_model_name,type(publish_relate_model_name))
    #<class 'app01.models.Publish'> <class 'django.db.models.base.ModelBase'>

    #取该字段相关联模型表的所有数据
    data_list=publish.rel.to.objects.all()
    print(data_list,type(data_list))
    #<QuerySet [<Publish: 苹果出版社>, <Publish: 光子出版社>]>   <class 'django.db.models.query.QuerySet'>

    return HttpResponse("OK")