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JPA: How to have one-to-many relation of the same Entity type
...em.persist(daughter);
em.getTransaction().commit();
}
In this case, all three entity instances must be persisted before transaction commit. If I fail to persist one of the entities in the graph of parent-child relationships, then an exception is thrown on commit(). On Eclipselink, this is a...
Easiest way to flip a boolean value?
...ses can be merged as they do the same thing.
– David Allan Finch
Mar 4 '09 at 15:16
1
Is default:...
The type or namespace name 'Objects' does not exist in the namespace 'System.Data'
... Server to create an n-tier app. I am creating some base classes common to all my DAL components. In this base class, i want to handle the connection state of the ObjectContext base class inherited by entities object.
...
View markdown files offline [closed]
...plug-ins that work well. I've been using Markdown Preview Plus.
After install, enable "Allow access to file URLs" in Extensions (menu > More tools > Extensions or enter URL chrome://extensions/ instead).
Then drag-n-drop a Markdown file onto Chrome and use your favorite editor to edit.
...
Creating an index on a table variable
...ds of adding constraint based indexes discussed below SQL Server 2014 also allows non unique indexes to be specified directly with inline syntax on table variable declarations.
Example syntax for that is below.
/*SQL Server 2014+ compatible inline index syntax*/
DECLARE @T TABLE (
C1 INT INDEX IX...
Language Books/Tutorials for popular languages
... online tutorials to learn programming languages or platforms. These generally give you no more than a little taste of the language. To really learn a language, you need the equivalent of a "book", and in many cases, this means a real dead-tree book.
If you want to learn C, read K&R. If you ...
What is the difference between a deep copy and a shallow copy?
What is the difference between a deep copy and a shallow copy?
31 Answers
31
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Nokogiri installation fails -libxml2 is missing
I always worked my way around Nokogiri installation issues by following the documentation in the " Installing Nokogiri " tutorial.
...
Force R not to use exponential notation (e.g. e+10)?
...
This is a bit of a grey area. You need to recall that R will always invoke a print method, and these print methods listen to some options. Including 'scipen' -- a penalty for scientific display. From help(options):
‘scipen’: integer. A penalty to be applied wh...
PostgreSQL error: Fatal: role “username” does not exist
...I can't do anything with PostgreSQL: can't createdb , can't createuser ; all operations return the error message
15 Answe...