How to use fn:contains(), fn:starts-with() and fn:ends-with in Optic API

问题

Earlier we used the FLOWR query to satisfy our search requirement, since data is getting increased day by day so we decided to use Indexing for better search performance.

Working FLOWR Query (Just Sample)

for $doc in collection("col1")
where fn:contains($doc//entityName/text(), "USA")
return document-uri($doc)

above query is working and it returns a document URI, Now we are trying to use Optic API to satisfy the same requirement.

We have created an element range index for entityName but not sure how to convert the above FLOWR query into Optic Query.

What will be equivalent Optic Query for the above FLOWR query ?, also in future we are planning to use fn:starts-with() and fn:ends-with() functions too.

We are using MarkLogic 10.0-2.1

Any help is appreciated

回答1:

After creating a TDE to project the entity properties, the equivalent Optic query would resemble the following in XQuery:

op:from-view(null, VIEW_NAME, '', op:fragment-id-col('docId'))
=> op:where(ofn:contains(op:col('entityName', 'USA'))
=> op:where(cts:collection-query(COLLECTION_NAME))
=> op:join-doc-uri('uri', op:fragment-id-col('docId'))
=> op:select('uri')
=> op:result()

In XQuery, the ofn library must be imported.

In SJS, the op.fn field provides the equivalent functions:

op.fromView(null, VIEW_NAME, '', op.fragmentIdCol('docId'))
  .where(op.fn.contains(op.col('entityName', 'USA'))
  .where(cts.collectionQuery(COLLECTION_NAME))
  .joinDocUri('uri', op.fragmentIdCol('docId'))
  .select('uri')
  .result()

The operations used:

fromView() accesses the entity view
The first where() filters on the value of the column during query execution
The second where() constrains the entity rows to matching source documents
The joinDocUri() joins the URI lexicon based on the source documents of the entity rows
The select() projects the 'uri' column, ignoring the unneeded view columns.

joinDocUri() is a convenience for

.joinInner(
    op.fromLexicons({'uri':cts.uriReference()}, '', op.fragmentIdCol('uriDocId')),
    op.on(op.fragmentIdCol('docId'), op.fragmentIdCol('uriDocId'))
    )

The Optic expression functions also include op.fn.startsWith() and op.fn.endsWith(). In general, Optic expressions can use a function if it both

is a builtin - in other words, doesn't require an import or require
only transforms its input to its output - in other words, is purely functional without side effects or environment sensitivity

See also this list of expression functions:

https://docs.marklogic.com/guide/app-dev/OpticAPI#id_69308

Hoping that helps,

来源：https://stackoverflow.com/questions/65911520/how-to-use-fncontains-fnstarts-with-and-fnends-with-in-optic-api

标签

marklogic

marklogic-10