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XQuery cts:element-values

MarkLogic 12 EA 1 Product Documentation
cts.elementValues

cts.elementValues(
   element-names as xs.QName[],
   [start as xs.anyAtomicType?],
   [options as String[]],
   [query as cts.query?],
   [quality-weight as Number?],
   [forest-ids as (Number|String)[]]
) as Sequence

Summary

Returns values from the specified element value lexicon(s). Value lexicons are implemented using range indexes; consequently this function requires an element range index for each element specified in the function. If there is not a range index configured for each of the specified elements, an exception is thrown.

Parameters
element-names One or more element QNames. If you specify multiple lexicons, they must all be over the same value type (string, int, etc.).
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:

"ascending"
Values should be returned in ascending order.
"descending"
Values should be returned in descending order.
"any"
Values from any fragment should be included.
"document"
Values from document fragments should be included.
"properties"
Values from properties fragments should be included.
"locks"
Values from locks fragments should be included.
"frequency-order"
Values should be returned ordered by frequency.
"item-order"
Values should be returned ordered by item.
"fragment-frequency"
Frequency should be the number of fragments with an included value. This option is used with cts:frequency.
"item-frequency"
Frequency should be the number of occurrences of an included value. This option is used with cts:frequency.
"type=type"
Use the lexicon with the type specified by type (int, unsignedInt, long, unsignedLong, float, double, decimal, dateTime, time, date, gYearMonth, gYear, gMonth, gDay, yearMonthDuration, dayTimeDuration, string, or anyURI)
"collation=URI"
Use the lexicon with the collation specified by URI.
"timezone=TZ"
Return timezone sensitive values (dateTime, time, date, gYearMonth, gYear, gMonth, and gDay) adjusted to the timezone specified by TZ. Example timezones: Z, -08:00, +01:00.
"limit=N"
Return no more than N words. You should not use this option with the "skip" option. Use "truncate" instead.
"skip=N"
Skip over fragments selected by the cts:query to treat the Nth fragment as the first fragment. Values from skipped fragments are not included. This option affects the number of fragments selected by the cts:query to calculate frequencies. Only applies when a $query parameter is specified.
"sample=N"
Return only values from the first N fragments after skip selected by the cts:query. This option does not affect the number of fragments selected by the cts:query to calculate frequencies. Only applies when a $query parameter is specified.
"truncate=N"
Include only values from the first N fragments after skip selected by the cts:query. This option also affects the number of fragments selected by the cts:query to calculate frequencies. Only applies when a $query parameter is specified.
"score-logtfidf"
Compute scores using the logtfidf method. Only applies when a $query parameter is specified.
"score-logtf"
Compute scores using the logtf method. Only applies when a $query parameter is specified.
"score-simple"
Compute scores using the simple method. Only applies when a $query parameter is specified.
"score-random"
Compute scores using the random method. Only applies when a $query parameter is specified.
"score-zero"
Compute all scores as zero. Only applies when a $query parameter is specified.
"checked"
Word positions should be checked when resolving the query.
"unchecked"
Word positions should not be checked when resolving the query.
"too-many-positions-error"
If too much memory is needed to perform positions calculations to check whether a document matches a query, return an XDMP-TOOMANYPOSITIONS error, instead of accepting the document as a match.
"eager"
Perform most of the work concurrently before returning the first item from the indexes, and only some of the work sequentially while iterating through the rest of the items. This usually takes the shortest time for a complete item-order result or for any frequency-order result.
"lazy"
Perform only some the work concurrently before returning the first item from the indexes, and most of the work sequentially while iterating through the rest of the items. This usually takes the shortest time for a small item-order partial result.
"concurrent"
Perform the work concurrently in another thread. This is a hint to the query optimizer to help parallelize the lexicon work, allowing the calling query to continue performing other work while the lexicon processing occurs. This is especially useful in cases where multiple lexicon calls occur in the same query (for example, resolving many facets in a single query).
"map"
Return results as a JavaScript Object instead of as a Sequence.
"coordinate-system=name"
Use the lexicon that is configured with the specified coordinate system. Allowed values: "wgs84", "wgs84/double", "raw", "raw/double". Only applicable if the lexicon value type is point or long-lat-point.
"precision=value"
Use the lexicon that is configured with the specified precision. Allowed values: float and double. Only applicable if the lexicon value type is point or long-lat-point. This value takes precedence over the precision implicit in the coordinate system name.
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 ().

Usage Notes

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.

Example

// an element range index must exist on "animal" or
// this example throws XDMP-ELEMRIDXNOTFOUND

  cts.elementValues(xs.QName("animal"),"aardvark")
  => ("aardvark","aardvarks","aardwolf",...)

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