One comment for whoever would like to use the same trick: it works as a
standalone command but not in a batch.
The root cause is probably the same as for the issue #3110
(https://github.com/orientechnologies/orientdb/issues/3110)
Too bad I'm using a batch... I'll have to wait for the issue to be fixed.
Le mardi 17 février 2015 15:16:14 UTC+1, Alain a écrit :
>
> Thank you Riccardo, that works (when moving the NOT before the IN : WHERE
> #9:1 NOT IN). It does what I need.
>
> One more question: with this solution, the SELECT is always done. So in
> terms of performance, is it better to run the SELECT and then run the
> CREATE if the result is not null or the CREATE FROM SELECT as you suggest
> is equivalent or even better ?
>
> Cheers,
> Alain
>
> Le mardi 17 février 2015 09:01:34 UTC+1, Riccardo Tasso a écrit :
>>
>> Hi, what about something like:
>>
>> CREATE EDGE knows FROM ( SELECT FROM #9:0 WHERE *NOT #9:1 IN
>> out('knows')* ) TO #9:1
>>
>> Cheers,
>> Riccardo
>>
>> 2015-02-16 18:41 GMT+01:00 Alain <[email protected]>:
>>
>>> Hi,
>>> I've started using OrientDB (version 2.0.2, remote protocol) last week.
>>> I have the exact same need as Dan (using ligthweight edges, no need for
>>> properties).
>>> However I believe the query that you suggested doesn't answer to the
>>> need as it prevents from creating more than one 'knows' edge per 'user'
>>> vertex however the goal is to prevent duplicate edges between 2 users (as
>>> in "one user can only be friend once with another user but can have several
>>> friends"). With your query, #9:0 can only have one 'knows'.
>>>
>>> Do you have any other suggestion (other than creating constraints) ?
>>>
>>> Thank you for your help.
>>>
>>> Cheers,
>>> Alain
>>>
>>>
>>> Le mercredi 7 janvier 2015 10:34:36 UTC+1, Riccardo Tasso a écrit :
>>>>
>>>> I would use the following query:
>>>>
>>>> CREATE EDGE knows FROM (SELECT FROM #9:0 WHERE out('knows') IS NULL) TO
>>>> #9:1
>>>>
>>>> In this way you won't have any exception if the edge already exists,
>>>> but it won't be inserted a duplicate.
>>>>
>>>> Cheers,
>>>> Riccardo
>>>>
>>>> 2015-01-07 9:50 GMT+01:00 Dan Andrei <[email protected]>:
>>>>
>>>>> Hello, I've looked for some info but I couldn't find anything clearly
>>>>> explained. My question is
>>>>>
>>>>> *How do I make a Edge unique in Orientdb ? version 1.7*
>>>>>
>>>>> The solution that I came up with:
>>>>>
>>>>> - delete the edge
>>>>> - create it again
>>>>>
>>>>> but it's not nice. Edge is without any properties.
>>>>>
>>>>> *Example:*
>>>>>
>>>>> create edge is_friend from #12:0 to #12:3
>>>>>
>>>>> and if I call it again, there should be an error like when you make a
>>>>> unique index.
>>>>>
>>>>> Lvca said Create a constraint on Edge out and in fields.
>>>>>
>>>>> But how exactly to do it ? I have a simple database with users and
>>>>> edges "is_friend" from user to user without any additional properties on
>>>>> the edge.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> http://www.orientechnologies.com/docs/last/orientdb.wiki/
>>>>> Graph-Schema.html#constraints
>>>>>
>>>>>
>>>>>
>>>>> Thank you very much
>>>>>
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>>>>>
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