[MarkLogic Dev General] Querying across 2 or more MarkLogic databases

Michael Blakeley mike at blakeley.com
Sun Mar 11 13:35:42 PDT 2012


I agree with Geert. While cross-database queries are possible, it's often better to use collections or directories rather than separate databases. For example, text search results are generally ranked by score. Scores are calculated per-database. So merging text search results between multiple databases may produce odd rankings.

-- Mike

On 11 Mar 2012, at 20:15 , Geert Josten wrote:

> Hi Betty,
> 
> Yes, you can use xdmp:invoke, or xdmp:eval for that purpose, but you'll
> have to combine results yourself in memory, so that comes with a penalty.
> Might be worth considering replication/syncing between databases..
> 
> Kind regards,
> Geert
> 
>> -----Oorspronkelijk bericht-----
>> Van: general-bounces at developer.marklogic.com [mailto:general-
>> bounces at developer.marklogic.com] Namens Danny Sinang
>> Verzonden: zondag 11 maart 2012 20:55
>> Aan: MarkLogic Developer Discussion
>> Onderwerp: Re: [MarkLogic Dev General] Querying across 2 or more
> MarkLogic
>> databases
>> 
>> I think you can do so using xdmp:invoke with an Options clause
>> specifying a different database. Assign the results of that query to a
>> variable and use it in other queries on other db's.
>> 
>> Sent from my iPhone
>> 
>> On Mar 11, 2012, at 3:21 PM, "Betty Harvey" <harvey at eccnet.com> wrote:
>> 
>>> Is it possible to query across databases in MarkLogic?  I need to
> query
>>> across multiple databases to get a single view of data.
>>> 
>>> I haven't been able to find if this is possible.
>>> 
>>> TIA!
>>> 
>>> Betty
>>> 
>>> 
>>> /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
>>> Betty Harvey                         | Phone:  410-787-9200  FAX: 9830
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