Search functions
These functions are used in conjunction with the @@ operator (the 'matches' operator) to either collect the relevance score or highlight the searched keywords within the content.
| Function | Description |
|---|---|
search::score() | Returns the relevance score |
search::highlight() | Highlights the matching keywords |
search::offsets() | Returns the position of the matching keywords |
The examples below assume the following queries:
CREATE book:1 SET title = "Rust Web Programming";
DEFINE ANALYZER book_analyzer TOKENIZERS blank, class, camel, punct FILTERS snowball(english);
DEFINE INDEX book_title ON book FIELDS title SEARCH ANALYZER book_analyzer BM25;
search::score
The search::score returns the relevance score corresponding to the given 'matches' predicate reference numbers.
API DEFINITIONsearch::score(number) -> number
The following example shows this function, and its output, when used in a RETURN statement:
SELECT id, title, search::score(1) AS score FROM book
WHERE title @1@ 'rust web'
ORDER BY score DESC;
[
{
id: book:1,
score: 0.9227996468544006,
title: [ 'Rust Web Programming' ],
}
]
search::highlight
The search::highlight highlights the matching keywords for the predicate reference number.
API DEFINITIONsearch::highlight(string, string, number, [boolean]) -> string | string[]
The following example shows this function, and its output, when used in a RETURN statement:
SELECT id, search::highlight('<b>', '</b>', 1) AS title
FROM book WHERE title @1@ 'rust web';
[
{
id: book:1,
title: [ '<b>Rust</b> <b>Web</b> Programming' ]
}
]
The optional Boolean parameter can be set to true to explicitly request that the whole found term be highlighted,
or set to false to highlight only the sequence of characters we are looking for. This must be used with an edgengram or ngram filter.
The default value is true.
search::offsets
The search::offsets returns the position of the matching keywords for the predicate reference number.
API DEFINITIONsearch::offsets(number, [boolean]) -> object
The following example shows this function, and its output, when used in a RETURN statement:
SELECT id, title, search::offsets(1) AS title_offsets
FROM book WHERE title @1@ 'rust web';
[
{
id: book:1,
title: [ 'Rust Web Programming' ],
title_offsets: {
0: [
{ e: 4, s: 0 },
{ e: 8, s: 5 }
]
}
}
]
The output returns the start s and end e positions of each matched term found within the original field.
The full-text index is capable of indexing both single strings and arrays of strings. In this example, the key 0 indicates that we're highlighting the first string within the title field, which contains an array of strings.
The optional Boolean parameter can be set to true to explicitly request that the whole found term be highlighted,
or set to false to highlight only the sequence of characters we are looking for. This must be used with an edgengram or ngram filter.
The default value is true.