Django __search 查找导致 FieldError

Question

我有一个

Pattern

对象的数据库，我想获取句子中包含字段

Pattern.substring

的所有模式：“这句话必须包含所有返回的 Pattern 对象”。

因此它返回例如具有这些

Pattern

值的

.substring

对象：

“这句话”,“全部”,“ce全部返回”....

所以我需要像反向查找这样的东西。据我所知，

__search

应该这样做，但它会引发错误：

Pattern.objects.filter(substring__search="This sentence has to contain all returned Pattern objects")

虽然我使用

django.db.backends.postgresql

，但它引发了：

FieldError：不支持对 CharField 进行查找“搜索”或不允许在该字段上进行连接。

你知道如何让它发挥作用吗？

完整追溯：

FieldError                                Traceback (most recent call last)
<ipython-input-16-80407f61e9e0> in <module>()
----> 1 Pattern.objects.filter(substring__search="This sentence has to contain all returned Pattern objects")

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/manager.py in manager_method(self, *args, **kwargs)
     80         def create_method(name, method):
     81             def manager_method(self, *args, **kwargs):
---> 82                 return getattr(self.get_queryset(), name)(*args, **kwargs)
     83             manager_method.__name__ = method.__name__
     84             manager_method.__doc__ = method.__doc__

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/query.py in filter(self, *args, **kwargs)
    834         set.
    835         """
--> 836         return self._filter_or_exclude(False, *args, **kwargs)
    837 
    838     def exclude(self, *args, **kwargs):

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/query.py in _filter_or_exclude(self, negate, *args, **kwargs)
    852             clone.query.add_q(~Q(*args, **kwargs))
    853         else:
--> 854             clone.query.add_q(Q(*args, **kwargs))
    855         return clone
    856 

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/sql/query.py in add_q(self, q_object)
   1251         # So, demotion is OK.
   1252         existing_inner = {a for a in self.alias_map if self.alias_map[a].join_type == INNER}
-> 1253         clause, _ = self._add_q(q_object, self.used_aliases)
   1254         if clause:
   1255             self.where.add(clause, AND)

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/sql/query.py in _add_q(self, q_object, used_aliases, branch_negated, current_negated, allow_joins, split_subq)
   1275                     child, can_reuse=used_aliases, branch_negated=branch_negated,
   1276                     current_negated=current_negated, allow_joins=allow_joins,
-> 1277                     split_subq=split_subq,
   1278                 )
   1279                 joinpromoter.add_votes(needed_inner)

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/sql/query.py in build_filter(self, filter_expr, branch_negated, current_negated, can_reuse, allow_joins, split_subq, reuse_with_filtered_relation)
   1213             col = targets[0].get_col(alias, join_info.final_field)
   1214 
-> 1215         condition = self.build_lookup(lookups, col, value)
   1216         lookup_type = condition.lookup_name
   1217         clause.add(condition, AND)

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/sql/query.py in build_lookup(self, lookups, lhs, rhs)
   1077             # A lookup wasn't found. Try to interpret the name as a transform
   1078             # and do an Exact lookup against it.
-> 1079             lhs = self.try_transform(lhs, lookup_name)
   1080             lookup_name = 'exact'
   1081             lookup_class = lhs.get_lookup(lookup_name)

~/.virtualenvs/ticketscrawler/lib/python3.6/site-packages/django/db/models/sql/query.py in try_transform(self, lhs, name)
   1113                 "Unsupported lookup '%s' for %s or join on the field not "
   1114                 "permitted." %
-> 1115                 (name, lhs.output_field.__class__.__name__))
   1116 
   1117     def build_filter(self, filter_expr, branch_negated=False, current_negated=False,

FieldError: Unsupported lookup 'search' for CharField or join on the field not permitted.

Answer 1

从 django 文档来看，此查询查找仅支持 MYSQL，并且从 django 1.10 开始已弃用。 https://docs.djangoproject.com/en/1.10/releases/1.10/#search-query-lookup。该链接上也提出了解决方案

from django.db import models

class Search(models.Lookup):
    lookup_name = 'search'

    def as_mysql(self, compiler, connection):
        lhs, lhs_params = self.process_lhs(compiler, connection)
        rhs, rhs_params = self.process_rhs(compiler, connection)
        params = lhs_params + rhs_params
        return 'MATCH (%s) AGAINST (%s IN BOOLEAN MODE)' % (lhs, rhs), params

models.CharField.register_lookup(Search)
models.TextField.register_lookup(Search)