django學習之model
阿新 • • 發佈:2021-08-20
定義兩個樣例模型:
class Role(models.Model): """ 角色 """ name = models.CharField(verbose_name='角色名稱', max_length=32, unique=True) permissions = models.ManyToManyField('Permission', verbose_name='許可權', blank=True) desc = models.CharField(verbose_name='描述', max_length=50, blank=True)class Meta: verbose_name = '角色' verbose_name_plural = verbose_name ordering = ['id'] def __str__(self): return self.name class Permission(models.Model): """ 許可權 """ name = models.CharField(verbose_name='許可權名稱', max_length=32, unique=True) path= models.CharField(verbose_name='URL', blank=True, max_length=128) method = models.CharField(verbose_name='方法', max_length=16, default='GET') pid = models.ForeignKey('self', verbose_name='上級許可權', null=True, blank=True, on_delete=models.SET_NULL) class Meta: verbose_name = '許可權' verbose_name_plural= verbose_name ordering = ['id'] def __str__(self): return self.name
一旦建立資料模型後,Django 自動給予你一套資料庫抽象 API,允許你建立,檢索,更新和刪除物件
一、model模型之資料查詢
1、用get()
檢索單個物件
若你知道只會有一個物件滿足查詢條件,你可以在Manager
上使用get()
方法,它會直接返回這個物件,可以通過object.field獲取欄位的值
In [1]: from apps.rbac.models import Role,Permission In [2]: role_object = Role.objects.get(id=2) In [3]: role_object Out[3]: <Role: member> In [4]: role_object.id Out[4]: 2 In [5]: role_object.name Out[5]: 'member'
2、ManyToManyField
多對多資料查詢方式
查詢某個角色有哪些許可權
In [1]: from apps.rbac.models import Role,Permission In [2]: role_object = Role.objects.get(id=2) In [6]: Permission.objects.filter(role=role_object) Out[6]: <QuerySet [<Permission: 檔案列表>, <Permission: 操作日誌>]> In [7]: Permission.objects.filter(role=role_object).values() Out[7]: <QuerySet [{'id': 3, 'name': '檔案列表', 'path': '/file/list', 'method': 'GET', 'pid_id': None}, {'id': 4, 'name': '操作日誌', 'path': '/file/operatelog', 'method': 'GET', 'pid_id': None}]> In [8]: Permission.objects.filter(role=role_object).values('path') Out[8]: <QuerySet [{'path': '/file/list'}, {'path': '/file/operatelog'}]> In [9]: Permission.objects.filter(role=role_object).values_list('path') Out[9]: <QuerySet [('/file/list',), ('/file/operatelog',)]> In [10]: list(Permission.objects.filter(role=role_object).values_list('path')) Out[10]: [('/file/list',), ('/file/operatelog',)] In [11]: list(Permission.objects.filter(role=role_object).values_list('path',flat=True)) Out[11]: ['/file/list', '/file/operatelog']
In [13]: Permission.objects.filter(role__id__contains=2)
Out[13]: <QuerySet [<Permission: 檔案列表>, <Permission: 操作日誌>]>
In [14]: list(Permission.objects.filter(role__id__contains=2).values_list('path',flat=True))
Out[14]: ['/file/list', '/file/operatelog']
二、model模型之資料寫入
1、儲存ForeignKey
和ManyToManyField
欄位
更新ForeignKey
欄位的方式與儲存普通欄位的方式相同——只需將正確型別的例項分配給相關欄位。本例為Entry
類的例項entry
更新了blog
屬性,假設Entry
和Blog
的例項均已儲存在資料庫中(因此能在下面檢索它們):
官方文件: >>> from blog.models import Blog, Entry >>> entry = Entry.objects.get(pk=1) >>> cheese_blog = Blog.objects.get(name="Cheddar Talk") >>> entry.blog = cheese_blog >>> entry.save() 實踐: productline = request.POST.get('productline').strip() file_list = { 'filename': file.name, 'productline': productline 'describe': request.POST.get('describe', ''), } FileProperty.objects.create(**file_list)