Solr search query parser usage analysis and overview

I. Introduction

　　Most queries using a standard Solr syntax. This syntax is the most common Solr, the default query parser handles. The default Solr Lucene query parser query parser class implementation] [LuceneQParserPlugin. Lucene query parser fully supports some proprietary extensions Lucene and Solr of grammar.

Two .Lucene query syntax parser

　　1. Field Search

　　　　When searching for a value in Solr index, it is generally look in a particular field. Search field syntax is: field name + ':' + searches, for example as follows:

　　　　title: solr or title: "apache solr" request_content_split :( process issues) Note: The brackets denote the set, each element separated by a space, meaning default representation OR

　　　　Although not explicitly specified keyword search field approach is very common, large should be noted that the general keyword search on the default fields defined. For example, if the content is defined as the default field] [df = content, the following two queries are equivalent:

　　　　solr or content: solr

　　　　Also note that the expression range of fields and the colon must be clearly defined. The following two queries are equivalent [assume] df = content, but users may be other intentions in the first query.

　　　　title:apache solr 或 title:apache content:solr

　　　　If you search for multiple terms in the same field, use a combination of expression specifying the scope of terms in the search field:

　　　　title:(apache solr)

　　　　If you try to search for a phrase, use quotation marks instead of brackets [] to define the scope of the phrase, although this will cause all terms in the query requires phrase must appear at the same time.

　　　　title:"apache solr"

　　2. The essential terms in use [less]

　　　　To specify one or more lexical items appear to be using unary + items to conjunctions. Unless the documents that contain the specified word entries, otherwise no match. If the document matching items must contain more than one word, using the binary operators AND or &&, or use the unary + entry for each word.

　　　　If the default operator is AND, in the absence of other designated operators, each lexical items are essential requirements. Because each additional item will be essential to further limit the total number of words resulting document set, so you can speed up queries by using a plurality of terms necessary to further optimize the number of results.

　　3. Optional lexical items

　　　　Compared necessary to limit the practice field, matching the expansion of the number of documents it is applicable to other cases. The default operator is OR, unless otherwise specified otherwise, each expression is optional. Similarly, using a binary operator OR or || between a plurality of expressions, which represents a document matching entry comprises at least one word.

　　　　It is worth noting that the more optional lexical items matching documents will lead to greater diversity, OR operational implementation costs higher than other Boolean operations. For search keywords, if the contents of a limited number, and hope the price was at the expense of precision, ensuring a higher return some results [recall], then consider using OR as the default operator. Because the document more optional lexical items matching usually results in a higher affinity score, use the OR as the default operator and ranked according to relevance scores, it is still possible to get that part of the results of the most relevant search results. However, the requirement to match all the different keywords that expand queries will get more some strange matches.

　　4. phrase search [less use, and must be used in the use of the word's field]

　　　　If you want to match multiple lexical items next to each other, use quotation marks to enclose them as a phrase. This query expression does not guarantee a match exactly the same text, the search field may contain a phrase in a term to modify the analyzer. The most reasonable of a particular search phrase should not be matched unrelated phrases. Phrase search process a particular field and multi-word name applies to the content.

　　The combination of expressions used []

　　　　To handle any complex Boolean clause, Solr use parentheses to combine query expressions.

　　　　Expression compositions may be provided in the context of the expression, for example, indicate a plurality of search words in the same field. Expression can be nested in any combination.