Thanks David.
Met vriendelijke groet,
Johan van den Brink
Consultant
Analyze That - Analytics | Data Integration | Reporting | Process Mining
Kerkewijk 8
3901 EG Veenendaal
T: (06) 49 92 30 30
T: (0318) 52 55 87
M: jo...@analyzethat.nlmailto:jo...@analyzethat.nl
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L: http://nl.linkedin.com/in/brinkjohanvanden
From: general-boun...@developer.marklogic.com
[mailto:general-boun...@developer.marklogic.com] On Behalf Of David Ennis
Sent: woensdag 4 juni 2014 23:32
To: MarkLogic Developer Discussion
Subject: Re: [MarkLogic Dev General] New Feature Request: Unique Value Range
Indexes
HI.
I believe you can do that here:
http://developer.marklogic.com/mailman/listinfo/general
Kind Regards,
David Ennis
On 4 June 2014 23:09, Analyze That | Johan van den Brink
jo...@analyzethat.nlmailto:jo...@analyzethat.nl wrote:
Hi guys,
How can I unsubscribe from this mailing list?
Met vriendelijke groet,
Johan van den Brink
Consultant
Analyze That - Analytics | Data Integration | Reporting | Process Mining
Kerkewijk 8
3901 EG Veenendaal
T: (06) 49 92 30 30
T: (0318) 52 55 87
M: jo...@analyzethat.nlmailto:jo...@analyzethat.nl
W: www.analyzethat.nlhttp://www.analyzethat.nl
L: http://nl.linkedin.com/in/brinkjohanvanden
-Original Message-
From:
general-boun...@developer.marklogic.commailto:general-boun...@developer.marklogic.com
[mailto:general-boun...@developer.marklogic.commailto:general-boun...@developer.marklogic.com]
On Behalf Of Whitby, Rob
Sent: woensdag 4 juni 2014 19:59
To: MarkLogic Developer Discussion
Subject: Re: [MarkLogic Dev General] New Feature Request: Unique Value Range
Indexes
How about something like this?
declare function unique-uri() {
let $uri := /doc/ || xdmp:random() || .xml
return if (fn:not(fn:doc-available($uri))) then $uri else unique-uri() };
I guess because indexes are distributed across forests, ensuring uniqueness is
not that easy?
Rob
From:
general-boun...@developer.marklogic.commailto:general-boun...@developer.marklogic.com
[general-boun...@developer.marklogic.commailto:general-boun...@developer.marklogic.com]
on behalf of Ron Hitchens [r...@ronsoft.commailto:r...@ronsoft.com]
Sent: 04 June 2014 18:01
To: MarkLogic Developer Discussion
Subject: [MarkLogic Dev General] New Feature Request: Unique Value Range
Indexes
I'm working on a project, one aspect of which requires minting unique IDs
and assuring that no two documents with the same ID wind up in the database. I
know how to accomplish this using locks (I'm pretty sure) but any such
implementation is awkward and prone to subtle edge case errors, and can be
difficult to test.
It seems to me that this is something that MarkLogic could do much more
reliably and quickly than any user-level code. The thought that occurred to me
is a variation on range indexes which only allow a single instance of any given
value.
Conventional range indexes work by creating term lists that look like this
(see Jason Hunter's ML Architecture paper), where each term list contains an
element (or attribute) value and a list of fragment IDs where that term exists.
aardvark | 23, 135, 469, 611
ant | 23, 469, 558, 611, 750
baboon | 53, 97, 469, 621
etc...
By making a range index like this but which only allows a single fragment ID
in the list, that would ensure that no two documents in the database contain a
given element with the same value. That is, attempting to add a second
document with the same element or attribute value would cause an exception.
And being a range index, it would provide a fast lexicon of all the current
unique values in the DB.
Such an index would look something like this:
abc3vk34 | 17
bkx46lkd | 52
bz1d34nm | 37
etc...
Usage could be something like this:
declare function create-new-id-doc ($id-root as xs:string) as xs:string {
try {
let $id := $id-root || - || mylib:random-string(8)
let $uri := /idregistry/id- || $id
let $_ :=
xdmp:document-insert ($uri,
registered-id
id{ $id }/id
created{ fn:current-dateTime() }/created
/registered-id
return $id
} catch (e) {
create-new-id-doc ($id-root)
}
};
This doesn't require that I write any (possibly buggy) mutual exclusion code
and I can be confident that once the xdmp:document-insert succeeds that the ID
is unique in the database and that the type (as configured for the range index)
is correct.
Any love for Unique Value Range Indexes in the next version of MarkLogic?
---
Ron Hitchens {r...@overstory.co.ukmailto:r...@overstory.co.uk} +44 7879
358212tel:%2B44%207879%20358212
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