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Rails: How do I create a default value for attributes in Rails activerecord's model? [duplicate]
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add_column :status, :string, :default => "P"
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OR
You can use a callback, before_save
class Task < ActiveRecord::Base
before_save :default_values
def default_values
self.status ||= 'P' # note self.status = 'P' if self.status.nil? might be safer (per @frontendbeauty)
end
end
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Cannot set some HTTP headers when using System.Net.WebRequest
...ts already or is restricted (WebHeaderCollection.IsRestricted(key)) before calling add
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How does the static modifier affect this code?
...A obj = new A();, so first it will create the object of that variable and call the constructor, hence the value of num1 and num2 becomes 1.
And then, again, static int num2=0; will be executed, which makes num2 = 0;.
Now, suppose your constructor is like this:
private A(){
num1++;
num2++...
Is there a way to simulate the C++ 'friend' concept in Java?
... }
}
So the method Juliet.cuddle is public but you need a Romeo.Love to call it. It uses this Romeo.Love as a "signature security" to ensure that only Romeo can call this method and checks that the love is real so that the runtime will throw a NullPointerException if it is null.
Now boys :
pack...
Compelling examples of custom C++ allocators?
...ctor would run first, then the delete of the custom allocator, which won't call free(...) yet, but free(...) would be called later, when serving the request has finished. This can be faster than the default allocator and reduce address space fragmentation.
– pts
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Does MySQL ignore null values on unique constraints?
...ted Oct 8 '18 at 13:50
Jon Schneider
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answered Sep 14 '10 at 19:34
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How to TryParse for Enum value?
...m.Val1|MyEnum.Val2" which is a combination of two enum values. If you just call Enum.IsDefined with this string, it will return false, even though Enum.Parse handles it correctly.
Update
As mentioned by Lisa and Christian in the comments, Enum.TryParse is now available for C# in .NET4 and up.
MSD...
Git branch diverged after rebase
...f you are collaborating with others on this branch, force pushing is a bad idea, as it will cause other collaborators to become very confused when their history suddenly doesn't match.
TL;DR - If you're not collaborating, push the branch using push -f. If you are, reset the branch to the previous ...
What is the difference between a directory and a folder?
...ole, but if accessed through a graphical file manager, users may sometimes call it a folder.
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How can I unit test Arduino code?
...an isolate discrete parts for testing.
If the parts that you want to test call any Arduino functions, you will need to provide mock-up replacements in your test program. This is much less work than it seems. Your mock-ups don't have to actually do anything but providing predictable input and outp...