Hi, Pragya: I'd like to make a different point:
* If you know exactly which document contains the information and need to inspect that document, use fn:doc() to read the document. * If you're not sure which document contains the information, use search (whether cts:search() or the JSearch or Search APIs) to match the document that contains the information. To put it the other way, avoid reading a large set of candidate documents with fn:doc and then checking each candidate document with XPaths to determine whether the candidate contains the information. (The equivalent to that antipattern in a relational database would be using a stored procedure to read and filter a large number of candidate rows instead of using an SQL WHERE clause to read only the appropriate rows.) Either way, after you have retrieved the correct document, the suggestions from the previous note apply to inspecting the document with XPaths. Hoping that clarifies, Erik Hennum ________________________________ From: [email protected] [[email protected]] on behalf of Kapoor, Pragya [[email protected]] Sent: Wednesday, January 27, 2016 9:52 PM To: MarkLogic Developer Discussion Subject: Re: [MarkLogic Dev General] If xml element exists Erik, If I understand correctly, you mean to say, if I know the document from where I need to fetch the elements, still the cts:search will be faster than fn:doc() For example: fn:doc("/misc/SavedTextSearches.xml")/TextSearches/User[Name = $User] ) (: slower :) cts:search(/TextSearches/User, cts:element-value-query(xs:QName("Name"), $User) (: faster:) Thanks Pragya ________________________________ From: [email protected] <[email protected]> on behalf of Erik Hennum <[email protected]> Sent: Wednesday, January 27, 2016 7:13 PM To: MarkLogic Developer Discussion Subject: Re: [MarkLogic Dev General] If xml element exists Hi, Pragya: If you need to retrieve the document anyway, you can test for the existence or absence of nodes with: http://docs.marklogic.com/fn:exists http://docs.marklogic.com/fn:empty as in let $root:= fn:doc("/misc/SavedTextSearches.xml")/TextSearches let $hasUser := ($root/User/Name/string(.) = $User) let $isHidden := fn:exists($root/Hidden) return ... To find documents of interest based on criteria, however, you should use cts:search() instead of fn:doc(), fn:doc() retrieves documents into memory before inspecting the document, where cts:search() matches against the indexes and thus (depending on the criteria) retrieves many fewer documents much more quickly. Hoping that helps, Erik Hennum ________________________________ From: [email protected] [[email protected]] on behalf of Kapoor, Pragya [[email protected]] Sent: Tuesday, January 26, 2016 10:32 PM To: MarkLogic Developer Discussion Subject: Re: [MarkLogic Dev General] If xml element exists Few more examples: if ($DocRecord[fn:not(.[Hidden])]) then () else $DocRecord if ($NumOfGroups = 1) then $DocRecords[fn:not(.[Hidden])] else () ________________________________ From: [email protected] <[email protected]> on behalf of Kapoor, Pragya <[email protected]> Sent: Wednesday, January 27, 2016 11:38 AM To: MarkLogic Developer Discussion Subject: [MarkLogic Dev General] If xml element exists Hi, I need to check the below conditions at multiple places, if there are other more performant way to achieve these: if ( fn:doc("/misc/SavedTextSearches.xml")/TextSearches/User[Name = $User] ) then "YES" else "NO" if ( fn:doc("/misc/SavedTextSearches.xml")/TextSearches ) then ( ) else 'p' Thanks Pragya "This e-mail and any attachments transmitted with it are for the sole use of the intended recipient(s) and may contain confidential , proprietary or privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this e-mail or any action taken in reliance on this e-mail is strictly prohibited and may be unlawful." "This e-mail and any attachments transmitted with it are for the sole use of the intended recipient(s) and may contain confidential , proprietary or privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this e-mail or any action taken in reliance on this e-mail is strictly prohibited and may be unlawful." "This e-mail and any attachments transmitted with it are for the sole use of the intended recipient(s) and may contain confidential , proprietary or privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this e-mail or any action taken in reliance on this e-mail is strictly prohibited and may be unlawful."
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