我正在关注this关于如何在Django应用中添加全文功能的帖子。我有以下模型：

class CustomUser(AbstractUser):
    email = models.EmailField(_('email address'), unique=True)

class Author(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL,on_delete = models.CASCADE)
    name = models.CharField(max_length = 250)
    alternative_names = ArrayField(models.CharField(max_length = 250),blank=True,null=True)
    name_norm = models.CharField(max_length = 250,blank=True,null = True)
    slug = models.CharField(max_length = 250,unique = True)
    photo = models.ImageField(upload_to = 'imgs/users/%Y/%m/%d',blank = True)

    search_vector = SearchVectorField(null=True)
    def save(self, *args, **kwargs):
        self.search_vector = (SearchVector('name', weight='A') )
        super().save(*args, **kwargs)`enter code here`

当我尝试用save保存一个新作者时：

autor = Author(user = utilizador,name = author_name,alternative_names = alternative_names,name_norm = name_norm,slug = slug)
    autor.save()

我得到错误：

Traceback (most recent call last):
  File "populate_v2.py", line 140, in <module>
    autor.save()
  File "/home/mwon/NewArquivoOpiniao/webapp/colunadeopiniao/accounts/models.py", line 57, in save
    super().save(*args, **kwargs)
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/base.py", line 748, in save
    self.save_base(using=using, force_insert=force_insert,
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/base.py", line 785, in save_base
    updated = self._save_table(
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/base.py", line 890, in _save_table
    results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/base.py", line 927, in _do_insert
    return manager._insert(
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/query.py", line 1204, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1393, in execute_sql
    for sql, params in self.as_sql():
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1336, in as_sql
    value_rows = [
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1337, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1337, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/home/mwon/NewArquivoOpiniao/env3.8/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1263, in prepare_value
    raise ValueError(
ValueError: Failed to insert expression "SearchVector(Col(accounts_author, accounts.Author.name), weight=A)" on accounts.Author.search_vector. F() expressions can only be used to update, not to insert.

Django版本：3.0.11

2条答案

按热度按时间

sr4lhrrt1#

F（）表达式只能用于更新，不能用于插入。
我不是VectorField的Maven，但可能是weight='A'导致了F()表达式。如果没有weight，它是否工作，如您参考的教程中所示？
否则，请尝试更新：

Author.objects.all().update(search_vector=SearchVector('name', weight='A'))

赞(0）回复(0）举报 2023-02-04

s71maibg2#

错误消息是说您在创建Author的新对象时试图向search_vector字段中插入一个值，但SearchVector类只支持更新现有对象，不支持创建新对象。要解决此问题，您可以更改save方法的实现，以便在创建对象后更新search_vector字段：

def save(self, *args, **kwargs):
    super().save(*args, **kwargs)
    Author.objects.filter(pk=self.pk).update(search_vector=SearchVector('name', weight='A'))

这样，可以先创建对象，然后更新向量。

无法使用PostgreSQL在Django全文搜索中保存新对象

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