cts.fieldValues( field-names as String[], [start as xs.anyAtomicType?], [options as String[]], [query as cts.query?], [quality-weight as Number?], [forest-ids as (Number|String)[]] ) as Sequence
Returns values from the specified field value lexicon(s). Value lexicons are implemented using range indexes; consequently this function requires an field range index for each field specified in the function. If there is not a range index configured for each of the specified fields, an exception is thrown.
Parameters | |
---|---|
field-names | One or more field names. |
start | A starting value. The parameter type must match the lexicon type. If the parameter value is not in the lexicon, then the values are returned beginning with the next value. |
options |
Options. The default is ().
Options include:
|
query |
Only include values in fragments selected by the cts:query ,
and compute frequencies from this set of included values.
The values do not need to match the query, but they must occur in
fragments selected by the query.
The fragments are not filtered to ensure they match the query,
but instead selected in the same manner as
"unfiltered" cts.search
operations. If a string
is entered, the string is treated as a cts:word-query of the
specified string.
|
quality-weight | A document quality weight to use when computing scores. The default is 1.0. |
forest-ids | A sequence of IDs of forests to which the search will be constrained. An empty sequence means to search all forests in the database. The default is (). |
This function returns a Sequence of
Value
objects, not native JavaScript values. In contexts
where loose equality is sufficient (e.g. '==' operator),
this distinction is transparent. However, in contexts where strict or
"same value" equality applies (e.g. '===' operator,
Array.prototype.includes
, Array.prototype.indexOf
),
comparison between an item in the Sequence and an equivalent native
value will fail. For details, see
Value Object in the JavaScript Reference Guide.
Only one of "frequency-order" or "item-order" may be specified in the options parameter. If neither "frequency-order" nor "item-order" is specified, then the default is "item-order".
Only one of "fragment-frequency" or "item-frequency" may be specified in the options parameter. If neither "fragment-frequency" nor "item-frequency" is specified, then the default is "fragment-frequency".
Only one of "ascending" or "descending" may be specified in the options parameter. If neither "ascending" nor "descending" is specified, then the default is "ascending" if "item-order" is specified, and "descending" if "frequency-order" is specified.
Only one of "eager" or "lazy" may be specified in the options parameter. If neither "eager" nor "lazy" is specified, then the default is "lazy" if "item-order" is specified, and "eager" if "frequency-order" is specified.
Only one of "any", "document", "properties", or "locks" may be specified in the options parameter. If none of "any", "document", "properties", or "locks" are specified and there is a $query parameter, then the default is "document". If there is no $query parameter then the default is "any".
Only one of the "score-logtfidf", "score-logtf", "score-simple", "score-random", or "score-zero" options may be specified in the options parameter. If none of "score-logtfidf", "score-logtf", "score-simple", "score-random", or "score-zero" are specified, then the default is "score-logtfidf".
Only one of the "checked" or "unchecked" options may be specified in the options parameter. If neither "checked" nor "unchecked" are specified, then the default is "checked".
If "collation=URI" is not specified in the options parameter, then the default collation is used. If a lexicon with that collation does not exist, an error is thrown.
If "sample=N" is not specified in the options parameter,
then all included values may be returned. If a $query
parameter
is not present, then "sample=N" has no effect.
If "truncate=N" is not specified in the options parameter,
then values from all fragments selected by the $query
parameter
are included. If a $query
parameter is not present, then
"truncate=N" has no effect.
To incrementally fetch a subset of the values returned by this function,
use
fn.subsequence
on the output, rather than
the "skip" option. The "skip" option is based on fragments matching the
query
parameter (if present), not on values. A fragment
matched by query might contain multiple values or no values.
The number of fragments skipped does not correspond to the number of
values. Also, the skip is applied to the relevance ordered query matches,
not to the ordered values list.
When using the "skip" option, use the "truncate" option rather than the "limit" option to control the number of matching fragments from which to draw values.
// If a field range index does not exist on "my_field", then // this example throws XDMP-FIELDRIDXNOTFOUND cts.fieldValues('my_field','John Goldings') // Returns output similar to the following: // ("John Goldings","Ooi Fu",...)
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