[英]Use custom join query with Django ManyToMany relationship
我有一個User
model,它通過 ManyToMany 連接到Role
model,然后Role
model 連接到兩個模型, SitePermission
或ForumPermission
。 問題是,我不知道如何設置該連接。
這是我的模型,(我相信)刪除了不相關的字段。
角色:
class Role():
class RoleTypes(models.TextChoices):
SITE = "s", "Site"
FORUM = "f", "Forum"
role_type = models.CharField(max_length=1, choices=RoleTypes.choices, null=True)
permissions = models.ManyToManyField(
"permissions.Permission",
related_name="roles",
through="permissions.RolePermissions",
)
角色權限:
class RolePermissions():
role = models.ForeignKey("permissions.Role", on_delete=models.PROTECT)
permission = models.ForeignKey("permissions.SitePermission", on_delete=models.PROTECT)
網站權限:
class SitePermissions():
permission = models.CharField(max_length=64)
論壇權限:
class SitePermissions():
permission = models.CharField(max_length=64)
forum = models.ForeignKey(
"forums.forum", db_column="forumId", on_delete=models.PROTECT
)
當然,問題是我無法將多個表連接到多對多。 If I was doing it in SQL, I'd have something like roles r LEFT JOIN role_permissions rp_s ON r.type = 's' and r.id = rp.role_id INNER JOIN site_permissions sp ON rp_s.permission_id = sp.id
with a forum_permissions 的第二組連接(例如,我知道 SQL 並不完全正確)。
那么有沒有辦法做到這一點? 有條件地鏈接到多個表? 或者我是否需要在Role
為每個SitePermission
和ForumPermission
擁有一個單獨的屬性,然后每個人都有邏輯來使用它?
嘗試
RolePermissions.objects.raw("roles r LEFT JOIN role_permissions rp_s ON r.type = 's' and r.id = rp.role_id INNER JOIN site_permissions sp ON rp_s.permission_id = sp.id")
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