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Rails: Why does find(id) raise an exception in rails? [duplicate]
...ctiveRecord, the default behaviour is to return nil or false for failures, and leave the exception control flow to methods ending in a bang (#save!).
– Marten Veldthuis
Aug 12 '11 at 8:07
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Hibernate, @SequenceGenerator and allocationSize
...nce by one , multiple this value by 50 (default allocationSize value) - and then uses this value as entity ID.
6 Answers...
How do I select an entire row which has the largest ID in the table?
...nique. I did some benchmarking using set profiling = 1; ...; show profiles and it appears our solutions have the same performance using MySQL. For my own knowledge, do you know what DBMS has poorer performance for subselects?
– unutbu
Feb 7 '14 at 20:08
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Distributed sequence number generation?
...m first seeing now.
You'll need to differentiate between sequence numbers and unique IDs that are (optionally) loosely sortable by a specific criteria (typically generation time). True sequence numbers imply knowledge of what all other workers have done, and as such require shared state. There is n...
Left Join With Where Clause
...tings`
ON `character_settings`.`setting_id` = `settings`.`id`
AND `character_settings`.`character_id` = '1'
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How to map a composite key with JPA and Hibernate?
...y the specification also applies. So here they are:
2.1.4 Primary Keys and Entity Identity
...
A composite primary key must
correspond to either a single
persistent field or property or to a
set of such fields or properties as
described below. A primary key class
must be defi...
How to find serial number of Android device?
I need to use a unique ID for an Android app and I thought the serial number for the device would be a good candidate. How do I retrieve the serial number of an Android device in my app ?
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How do I perform the SQL Join equivalent in MongoDB?
...t array field>
}
}
Of course Mongo is not a relational database, and the devs are being careful to recommend specific use cases for $lookup, but at least as of 3.2 doing join is now possible with MongoDB.
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What is the purpose of Android's tag in XML layouts?
... Romain Guy's post on the <merge /> tag, but I still don't understand how it's useful. Is it a sort-of replacement of the <Frame /> tag, or is it used like so:
...
Get img thumbnails from Vimeo?
...r.
output Specify the
output type. We currently offer JSON,
PHP, and XML formats.
So getting this URL http://vimeo.com/api/v2/video/6271487.xml
<videos>
<video>
[skipped]
<thumbnail_small>http://ts.vimeo.com.s3.amazonaws.com/235/662/23566238...