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How to declare std::unique_ptr and what is the use of it?
...g a unique_ptr from a raw pointer), but the second approach is potentially more dangerous, since it would allow you, for instance, to do:
unique_ptr<double> uptr2 (pd);
// ...
unique_ptr<double> uptr3 (pd);
Thus having two unique pointers that effectively encapsulate the same object (...
Is it possible to hide the cursor in a webpage using CSS or Javascript?
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delete_all vs destroy_all?
...l
You can do :
u = User.find_by_name('JohnBoy')
UsageIndex.destroy_all "user_id = #{u.id}"
The result is one query to destroy all the associated records
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What is an MvcHtmlString and when should I use it?
...d on opinion; back them up with references or personal experience.To learn more, see our tips on writing great answers.
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How can I send an HTTP POST request to a server from Excel using VBA?
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@Leviathan the parens actually do more than that: they make the VBA runtime evaluate the expression as a value, and pass it to the method ByVal regardless of whether the method's signature says ByRef or not. That's why using them with object variables of a ty...
What is the meaning of the CascadeType.ALL for a @ManyToOne JPA association
...dresses {
@ManyToOne(cascade = CascadeType.REFRESH) @JoinColumn(name = "user_id")
protected User addressOwner;
}
This way you dont need to worry about using fetch in annotations. But remember when deleting the User you will also delete connected address to user object.
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Where are Docker images stored on the host machine?
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What is the difference between new/delete and malloc/free?
... the size)
Has a version explicitly to handle arrays.
Reallocating (to get more space) not handled intuitively (because of copy constructor).
Whether they call malloc/free is implementation defined.
Can add a new memory allocator to deal with low memory (set_new_handler)
operator new/delete can be o...
Conditional HTML Attributes using Razor MVC3
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how to permit an array with strong parameters
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params.require(:question).permit(:question_details, :question_content, :user_id, :accepted_answer_id, :province_id, :city, :category_ids => [])
Works perfectly now!
(IMPORTANT: As @Lenart notes in the comments, the array declarations must be at the end of the attributes list, otherwise you'...