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@UniqueConstraint annotation in Java
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I'm currently using play framework too with hibernate and JPA 2.0 annotation and this model works without problems
@Entity
@Table(uniqueConstraints={@UniqueConstraint(columnNames = {"id_1" , "id_2"})})
public class class_name {
@Id
@GeneratedValue
public Long id;
@Not...
In C#, what happens when you call an extension method on a null object?
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I was referring to the difference between call and callvirt il instructions. In one edit I actually tried to href the two Opcodes pages, but the editor barfed at the links...
– Marc Gravell♦
May 11 '09 at 9:48
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How can I reorder my divs using only CSS?
... in that order in the HTML? Both div s contain data that varies in height and width.
24 Answers
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Where can I find my Facebook application id and secret key?
...rom 2018:
Go to Settings -> Basic -> App Secret (type your password and you're ready to go).
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Django “xxxxxx Object” display customization in admin action sidebar
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Using the __str__ method works on Python3 and Django1.8:
class MyModel(models.Model):
name = models.CharField(max_length=60)
def __str__(self):
return 'MyModel: {}'.format(self.name)
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How do I erase an element from std::vector by index?
I have a std::vector, and I want to delete the n'th element. How do I do that?
15 Answers
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Executors.newCachedThreadPool() versus Executors.newFixedThreadPool()
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I think the docs explain the difference and usage of these two functions pretty well:
newFixedThreadPool
Creates a thread pool that reuses a
fixed number of threads operating off
a shared unbounded queue. At any
point, at most nThreads threads will
be...
How to concatenate strings in django templates?
... just works. Though I would recommend Ahsan's own answer as it also workes and is (in my opinion) semantically more correct and raises less confusion.
– gitaarik
Apr 2 '13 at 16:23
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convert a char* to std::string
...ing str(s);
Note that this construct deep copies the character list at s and s should not be nullptr, or else behavior is undefined.
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On localhost, how do I pick a free port number?
I'm trying to play with inter-process communication and since I could not figure out how to use named pipes under Windows I thought I'll use network sockets. Everything happens locally. The server is able to launch slaves in a separate process and listens on some port. The slaves do their work and s...