Terms
A query is broken up into terms and operators. There are two types of terms: Single Terms and Phrases.
A Single Term is a single word such as "test" or "hello".
A Phrase is a group of words surrounded by double quotes such as "hello dolly".
Multiple terms can be combined together with Boolean operators to form a more complex query (see below).
Term Modifiers
Search supports modifying query terms to provide a wide range of searching options.
Wildcard Searches
Search supports single and multiple character wildcard searches within single terms (not within phrase queries).
To perform a single character wildcard search use the "?" symbol.
To perform a multiple character wildcard search use the "*" symbol.
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:
te?t
Multiple character wildcard searches looks for 0 or more characters. For example, to search for test, tests or tester, you can use the search:
test*
You can also use the wildcard searches in the middle of a term.
te*t
Note: You cannot use a * or ? symbol as the first character of a search.
Fuzzy Searches
Search 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:
roam~
This search will find terms like foam and roams.
Starting with Search 1.9 an additional (optional) parameter can specify the required similarity. The value is between 0 and 1, with a value closer to 1 only terms with a higher similarity will be matched. For example:
roam~0.8
The default that is used if the parameter is not given is 0.5.
Proximity Searches
Search 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 "star" and "gas" within 10 words of each other in a document use the search:
"gas star"~10
Boosting a Term
Search 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.
Boosting allows you to control the relevance of a document by boosting its term. For example, if you are searching for
gas star
and you want the term "gas" to be more relevant boost it using the ^ symbol along with the boost factor next to the term. You would type:
gas^4 star
This will make documents with the term jakarta appear more relevant. You can also boost Phrase Terms as in the example:
"gas star"^4 "cosmic origins"
By default, the boost factor is 1. Although the boost factor must be positive, it can be less than 1 (e.g. 0.2)
Boolean Operators
Boolean operators allow terms to be combined through logic operators. Search supports AND, "+", OR, NOT and "-" as Boolean operators(Note: Boolean operators must be ALL CAPS).
The AND operator is the default conjunction operator. This means that if there is no Boolean operator between two terms, the AND operator is used. The AND operator links two terms and finds a matching document if both of the terms exist in a document. The symbol && can be used in place of the word AND.
To search for documents that contain both "gas star" and just "gas" use the query:
"gas star" gas
or
"gas star" AND gas
OR
The OR operator matches documents where either terms exist anywhere in the text of a single document. The symbol || can be used in place of the word OR.
To search for documents that contain "gas star" or "cosmic origins" use the query:
"gas star" OR "cosmic origins"
NOT
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.
To search for documents that contain "gas star" but not "cosmic origins" use the query:
"gas star" NOT "cosmic origins"
Note: The NOT operator cannot be used with just one term. For example, the following search will return no results:
NOT "gas star"
-
The "-" or prohibit operator excludes documents that contain the term after the "-" symbol.
To search for documents that contain "gas star" but not "cosmic origins" use the query:
"gas star" -"cosmic origins"
Grouping
Search 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.
To search for either "gas" or "star" and "nebula" use the query:
(gas OR star) AND nebula
This eliminates any confusion and makes sure you that nebula must exist and either term gas or star may exist.
Escaping Special Characters
Search supports escaping special characters that are part of the query syntax. The current list special characters are
+ - && || ! ( ) { } [ ] ^ " ~ * ? : \
To escape these character use the \ before the character. For example to search for (1+1):2 use the query:
\(1\+1\)\:2