如何在多个字段上使用 SearchHeadline 和 SearchVector
我需要一个搜索多个字段并返回一个突出显示匹配单词的“标题”。我的理解是 SearchVector 是跨多个字段搜索的合适选择。但我见过的所有 SearchHeadline 示例都只使用一个字段！将 SearchHeadline 与多个字段结合使用的最佳方式是什么？例如，这有效：
return (
Author.objects
.annotate(search_vectors=SearchVector('name', 'location'), )
.filter(search_vectors=SearchQuery(search_string))
)
简单。所以下一步是添加 SearchHeadline...这是我的猜测，但它会导致 PostgreSQL 中出现错误：
return (
Author.objects
.annotate(search_vectors=SearchVector('name', 'location'), )
.annotate(headline=SearchHeadline(
SearchVector('name', 'location'),
SearchQuery(search_string),
start_sel='<strong>', stop_sel='</strong>'))
.filter(search_vectors=SearchQuery(search_string))
)
错误：
Traceback (most recent call last):
File "/vagrant/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
psycopg2.errors.UndefinedFunction: function ts_headline(tsvector, tsquery, unknown) does not exist
LINE 1: ...app_author"."location", '')) AS "search_vectors", ts_headlin...
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
SearchVector() 不是有效的表达式吗？
使用 Concat() 可以完成工作，但这不允许我利用 ts_vector 的内置索引功能。对我来说这感觉像是一个黑客解决方案。
return (
Author.objects
.annotate(search_vectors=SearchVector('name', 'location'), )
.annotate(headline=SearchHeadline(
Concat(F('name'), Value(' '), F('location')),
SearchQuery(search_string),
start_sel='<strong>', stop_sel='</strong>'))
.filter(search_vectors=SearchQuery(search_string))
)
最好的方法是什么？
I need a search that searches multiple fields and returns a "headline" which highlights the matching words. My understanding is that SearchVector is the appropriate choice for searching across multiple fields. But all of the examples I've seen of SearchHeadline use only a single field! What's the best way to use SearchHeadline with multiple fields? For example, this works:
return (
Author.objects
.annotate(search_vectors=SearchVector('name', 'location'), )
.filter(search_vectors=SearchQuery(search_string))
)
Easy. So the next step is to add SearchHeadline... Here was my guess, but it causes an error in PostgreSQL:
return (
Author.objects
.annotate(search_vectors=SearchVector('name', 'location'), )
.annotate(headline=SearchHeadline(
SearchVector('name', 'location'),
SearchQuery(search_string),
start_sel='<strong>', stop_sel='</strong>'))
.filter(search_vectors=SearchQuery(search_string))
)
Error:
Traceback (most recent call last):
File "/vagrant/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
psycopg2.errors.UndefinedFunction: function ts_headline(tsvector, tsquery, unknown) does not exist
LINE 1: ...app_author"."location", '')) AS "search_vectors", ts_headlin...
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
Is SearchVector() not a valid expression?
Using Concat() gets the job done, but this doesn't allow me to leverage the built in indexing capabilities of a ts_vector. It feels like a hack solution to me.
return (
Author.objects
.annotate(search_vectors=SearchVector('name', 'location'), )
.annotate(headline=SearchHeadline(
Concat(F('name'), Value(' '), F('location')),
SearchQuery(search_string),
start_sel='<strong>', stop_sel='</strong>'))
.filter(search_vectors=SearchQuery(search_string))
)
What's the best way to do this?
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评论（1）
我看不到任何使用 tsvector 的可能性。
查看文档。
ts_headline 使用原始文档，而不是 tsvector 摘要，因此它可能很慢，应谨慎使用。
https://www.postgresql.org/docs/current/textsearch-controls。 html
一般来说，您的解决方法是（独特的）解决方案
:-)
I don't see any possibility to use a tsvector.
Have a look in the documentation.
ts_headline uses the original document, not a tsvector summary, so it can be slow and should be used with care.
https://www.postgresql.org/docs/current/textsearch-controls.html
in general your workaround is the (unique) solution
:-)