Lucene，查询中的某些关键字（例如，范围查询中的“TO”）区分大小写

Question

在Lucene中，由于标准分析器，搜索默认情况下对用户不敏感。这是用户期望的，并且工作正常。

但是，对于范围查询中的“TO”或“AND”/“OR”等几个词，这些关键字区分大小写。这不是用户的期望。

1. 这有什么理由吗？ Lucene在默认情况下基本上“正常工作”，所以有点惊讶。也许背后有一个很好的理由，我不应该碰它。
2. 我如何才能使这些关键字不区分大小写？由于默认情况下查询的其余部分不区分大小写，我可以将整个查询转换为大写？如果我这样做，我会遇到什么问题吗？还有更好的方法吗？

Answer 1

Is there a reason for this?

The real question here might not be "why does lucene do this?", but rather "why does google do this?", as I believe Google's use of this pattern predates Lucene's. Regardless, though, the reasoning isn't too hard to deduce. There needs to be a way of differentiating the word "and" from the the query operator "AND".

Say my query is: Jack and Jill went up the hill

I'm just searching a phrase that happens to contain the word "and". The end result I want is (eliminating stop words, and such):

field:jack field:jill field:went field:up field:hill

Rather than:

+field:jack +field:jill field:went field:up field:hill

If the word is uppercased, it's a decent indicator the user intended the word as an operator.

If all ands became operands, users might be confused why a search for "bread and butter pickles" (becomes +bread +butter pickles) turns up hits about toast, but not about other types of pickles.

Similar for lists of things, like "Abby, Ben, Chris, Dave and Elmer" (becomes abby ben chris +dave +elmer), which all hits would require Dave and Elmer to be present, but the rest of the names would be optional.

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How to make them case insensitive?

Uppercasing the whole thing, or every instance of an AND, OR or TO, could be a bit promblematic. Take these, for example:

• [to TO tz] works, [TO TO TZ] throws an exception
• and another thing works, AND ANOTHER THING throws an exception

You could check for a ParseException after uppercasing, and try parsing the original query in that case. Might create a bit of an inconsistency, but it beats just failing entirely.