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| <document> |
| <properties> |
| <author email="carlson@apache.org">Peter Carlson</author> |
| <title> |
| Query Parser Syntax - Jakarta Lucene |
| </title> |
| </properties> |
| <body> |
| <section name="Overview"> |
| <p>Although Lucene provides the ability to create your own |
| queries through its API, it also provides a rich query |
| language through the Query Parser.</p> <p>This page |
| provides syntax of Lucene's Query Parser, a lexer which |
| interprets a string into a Lucene Query using JavaCC.</p> |
| <p> |
| Before choosing to use the provided Query Parser, please consider the following: |
| <ol> |
| <li>If you are programmatically generating a query string and then |
| parsing it with the query parser then you should seriously consider building |
| your queries directly with the query API. In other words, the query |
| parser is designed for human-entered text, not for program-generated |
| text.</li> |
| |
| <li>Untokenized fields are best added directly to queries, and not |
| through the query parser. If a field's values are generated programmatically |
| by the application, then so should query clauses for this field. |
| An analyzer, which the query parser uses, is designed to convert human-entered |
| text to terms. Program-generated values, like dates, keywords, etc., |
| should be consistently program-generated.</li> |
| |
| <li>In a query form, fields which are general text should use the query |
| parser. All others, such as date ranges, keywords, etc. are better added |
| directly through the query API. A field with a limit set of values, |
| that can be specified with a pull-down menu should not be added to a |
| query string which is subsequently parsed, but rather added as a |
| TermQuery clause.</li> |
| </ol> |
| </p> |
| </section> |
| |
| <section name="Terms"> |
| <p>A query is broken up into terms and operators. There are two types of terms: Single Terms and Phrases.</p> |
| <p>A Single Term is a single word such as "test" or "hello".</p> |
| <p>A Phrase is a group of words surrounded by double quotes such as "hello dolly".</p> |
| <p>Multiple terms can be combined together with Boolean operators to form a more complex query (see below).</p> |
| <p>Note: The analyzer used to create the index will be used on the terms and phrases in the query string. |
| So it is important to choose an analyzer that will not interfere with the terms used in the query string.</p> |
| </section> |
| |
| <section name="Fields"> |
| <p>Lucene supports fielded data. When performing a search you can either specify a field, or use the default field. The field names and default field is implementation specific.</p> |
| <p>You can search any field by typing the field name followed by a colon ":" and then the term you are looking for. </p> |
| <p>As an example, let's assume a Lucene index contains two fields, title and text and text is the default field. |
| If you want to find the document entitled "The Right Way" which contains the text "don't go this way", you can enter: </p> |
| |
| <source>title:"The Right Way" AND text:go</source> |
| <p>or</p> |
| <source>title:"Do it right" AND right</source> |
| <p>Since text is the default field, the field indicator is not required.</p> |
| |
| <p>Note: The field is only valid for the term that it directly precedes, so the query</p> |
| <source>title:Do it right</source> |
| <p>Will only find "Do" in the title field. It will find "it" and "right" in the default field (in this case the text field). </p> |
| </section> |
| |
| <section name="Term Modifiers"> |
| |
| <p>Lucene supports modifying query terms to provide a wide range of searching options.</p> |
| |
| <subsection name="Wildcard Searches"> |
| <p>Lucene supports single and multiple character wildcard searches.</p> |
| <p>To perform a single character wildcard search use the "?" symbol.</p> |
| <p>To perform a multiple character wildcard search use the "*" symbol.</p> |
| <p>The single character wildcard search looks for terms that match that with the single character replaced. For example, to search for "text" or "test" you can use the search:</p> |
| |
| <source>te?t</source> |
| |
| <p>Multiple character wildcard searches looks for 0 or more characters. For example, to search for test, tests or tester, you can use the search: </p> |
| <source>test*</source> |
| <p>You can also use the wildcard searches in the middle of a term.</p> |
| <source>te*t</source> |
| <p>Note: You cannot use a * or ? symbol as the first character of a search.</p> |
| </subsection> |
| |
| |
| <subsection name="Fuzzy Searches"> |
| <p>Lucene supports fuzzy searches based on the Levenshtein Distance, or Edit Distance algorithm. To do a fuzzy search use the tilde, "~", symbol at the end of a Single word Term. For example to search for a term similar in spelling to "roam" use the fuzzy search: </p> |
| |
| <source>roam~</source> |
| <p>This search will find terms like foam and roams</p> |
| </subsection> |
| |
| |
| <subsection name="Proximity Searches"> |
| <p>Lucene supports finding words are a within a specific distance away. To do a proximity search use the tilde, "~", symbol at the end of a Phrase. For example to search for a "apache" and "jakarta" within 10 words of each other in a document use the search: </p> |
| |
| <source>"jakarta apache"~10</source> |
| </subsection> |
| |
| |
| <subsection name="Range Searches"> |
| <p>Range Queries allow one to match documents whose field(s) values |
| are between the lower and upper bound specified by the Range Query. |
| Range Queries can be inclusive or exclusive of the upper and lower bounds. |
| Sorting is done lexicographically.</p> |
| <source>mod_date:[20020101 TO 20030101]</source> |
| <p>This will find documents whose mod_date fields have values between 20020101 and 20030101, inclusive. |
| Note that Range Queries are not reserved for date fields. You could also use range queries with non-date fields:</p> |
| <source>title:{Aida TO Carmen}</source> |
| <p>This will find all documents whose titles are between Aida and Carmen, but not including Aida and Carmen.</p> |
| <p>Inclusive range queries are denoted by square brackets. Exclusive range queries are denoted by |
| curly brackets.</p> |
| </subsection> |
| |
| |
| <subsection name="Boosting a Term"> |
| <p>Lucene provides the relevance level of matching documents based on the terms found. To boost a term use the caret, "^", symbol with a boost factor (a number) at the end of the term you are searching. The higher the boost factor, the more relevant the term will be.</p> |
| <p>Boosting allows you to control the relevance of a document by boosting its term. For example, if you are searching for</p> |
| |
| <source>jakarta apache</source> |
| <p>and you want the term "jakarta" to be more relevant boost it using the ^ symbol along with the boost factor next to the term. |
| You would type:</p> |
| <source>jakarta^4 apache</source> |
| <p>This will make documents with the term jakarta appear more relevant. You can also boost Phrase Terms as in the example: </p> |
| |
| <source>"jakarta apache"^4 "jakarta lucene"</source> |
| <p>By default, the boost factor is 1. Although the boost factor must be positive, it can be less than 1 (e.g. 0.2)</p> |
| </subsection> |
| |
| </section> |
| |
| |
| <section name="Boolean operators"> |
| |
| <p>Boolean operators allow terms to be combined through logic operators. |
| Lucene supports AND, "+", OR, NOT and "-" as Boolean operators(Note: Boolean operators must be ALL CAPS).</p> |
| |
| <subsection name="OR"> |
| <p>The OR operator is the default conjunction operator. This means that if there is no Boolean operator between two terms, the OR operator is used. |
| The OR operator links two terms and finds a matching document if either of the terms exist in a document. This is equivalent to a union using sets. |
| The symbol || can be used in place of the word OR.</p> |
| <p>To search for documents that contain either "jakarta apache" or just "jakarta" use the query:</p> |
| |
| <source>"jakarta apache" jakarta</source> |
| |
| <p>or</p> |
| |
| <source>"jakarta apache" OR jakarta</source> |
| |
| </subsection> |
| <subsection name="AND"> |
| <p>The AND operator matches documents where both terms exist anywhere in the text of a single document. |
| This is equivalent to an intersection using sets. The symbol && can be used in place of the word AND.</p> |
| <p>To search for documents that contain "jakarta apache" and "jakarta lucene" use the query: </p> |
| |
| <source>"jakarta apache" AND "jakarta lucene"</source> |
| </subsection> |
| |
| <subsection name="+"> |
| <p>The "+" or required operator requires that the term after the "+" symbol exist somewhere in a the field of a single document.</p> |
| <p>To search for documents that must contain "jakarta" and may contain "lucene" use the query:</p> |
| |
| <source>+jakarta apache</source> |
| </subsection> |
| |
| <subsection name="NOT"> |
| <p>The NOT operator excludes documents that contain the term after NOT. |
| This is equivalent to a difference using sets. The symbol ! can be used in place of the word NOT.</p> |
| <p>To search for documents that contain "jakarta apache" but not "jakarta lucene" use the query: </p> |
| |
| <source>"jakarta apache" NOT "jakarta lucene"</source> |
| <p>Note: The NOT operator cannot be used with just one term. For example, the following search will return no results:</p> |
| |
| <source>NOT "jakarta apache"</source> |
| </subsection> |
| |
| <subsection name="-"> |
| <p>The "-" or prohibit operator excludes documents that contain the term after the "-" symbol.</p> |
| <p>To search for documents that contain "jakarta apache" but not "jakarta lucene" use the query: </p> |
| |
| <source>"jakarta apache" -"jakarta lucene"</source> |
| </subsection> |
| |
| </section> |
| |
| <section name="Grouping"> |
| <p>Lucene supports using parentheses to group clauses to form sub queries. This can be very useful if you want to control the boolean logic for a query.</p> |
| <p>To search for either "jakarta" or "apache" and "website" use the query:</p> |
| <source>(jakarta OR apache) AND website</source> |
| <p>This eliminates any confusion and makes sure you that website must exist and either term jakarta or apache may exist.</p> |
| </section> |
| |
| <section name="Field Grouping"> |
| <p>Lucene supports using parentheses to group multiple clauses to a single field.</p> |
| <p>To search for a title that contains both the word "return" and the phrase "pink panther" use the query:</p> |
| <source>title:(+return +"pink panther")</source> |
| </section> |
| |
| <section name="Escaping Special Characters"> |
| <p>Lucene supports escaping special characters that are part of the query syntax. The current list special characters are</p> |
| <p>+ - && || ! ( ) { } [ ] ^ " ~ * ? : \</p> |
| <p>To escape these character use the \ before the character. For example to search for (1+1):2 use the query:</p> |
| <source>\(1\+1\)\:2</source> |
| </section> |
| |
| </body> |
| </document> |