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JPA: How to have one-to-many relation of the same Entity type
... the relationship is the same. The general case is detailed in Section 2.10.2 of the JPA 2.0 spec.
Here's a worked example. First, the entity class A:
@Entity
public class A implements Serializable {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
@ManyToOne
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Node.js and CPU intensive requests
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answered Aug 21 '10 at 3:39
TimTim
1,93522 gold badges2020 silver badges1818 bronze badges
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What is the best way to use a HashMap in C++?
...gt;first << " Value: " << i->second << '\n';
return 0;
}
Output:
23
Key: hello Value: 23
If you need ordering in your container and are fine with the O(log n) runtime then just use std::map.
Otherwise, if you really need a hash-table (O(1) insert/access), check out std:...
RabbitMQ and relationship between channel and connection
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201
A Connection represents a real TCP connection to the message broker, whereas a Channel is a vi...
How does one make an optional closure in swift?
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answered Jun 24 '14 at 20:46
CezarCezar
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What is a Y-combinator? [closed]
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206
If you're ready for a long read, Mike Vanier has a great explanation. Long story short, it allo...
How expensive is RTTI?
...e in runtime memory usage.
A quick experiment (using GCC 4.4.3 on Ubuntu 10.04 64-bit) shows that -fno-rtti actually increases the binary size of a simple test program by a few hundred bytes. This happens consistently across combinations of -g and -O3. I'm not sure why the size would increase; one ...
Can I set a breakpoint on 'memory access' in GDB?
...ad/write.
You can set read watchpoints on memory locations:
gdb$ rwatch *0xfeedface
Hardware read watchpoint 2: *0xfeedface
but one limitation applies to the rwatch and awatch commands; you can't use gdb variables
in expressions:
gdb$ rwatch $ebx+0xec1a04f
Expression cannot be implemented with ...
What difference is there between WebClient and HTTPWebRequest classes in .NET?
...asic auth wrong, require weird workarounds like ServicePointManager.Expect100Continue = false, do other non-standard things and have many quirks and idiosyncrasies. I started RestSharp to help smooth out those problems.
– John Sheehan
Feb 14 '11 at 2:30
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When to use a “has_many :through” relation in Rails?
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edited Dec 1 '15 at 10:07
Arslan Ali
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answer...