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What does the explicit keyword mean?
...hat takes a Foo object:
void DoBar (Foo foo)
{
int i = foo.GetFoo ();
}
and here's where the DoBar function is called:
int main ()
{
DoBar (42);
}
The argument is not a Foo object, but an int. However, there exists a constructor for Foo that takes an int so this constructor can be used to conv...
Create unique constraint with null columns
...(user_id, menu_id, recipe_id), you cannot base CLUSTER on a partial index, and queries without a matching WHERE condition cannot use the partial index. (It seems unlikely you'd want a FK reference three columns wide - use the PK column instead).
If you need a complete index, you can alternatively d...
How can I check for “undefined” in JavaScript? [duplicate]
.../ true
As @CMS pointed out, this has been patched in ECMAScript 5th ed., and undefined is non-writable.
if (window.myVar) will also include these falsy values, so it's not very robust:
false
0
""
NaN
null
undefined
Thanks to @CMS for pointing out that your third case - if (myVariable) can als...
How to auto-reload files in Node.js?
...rvisor is nodemon:
Monitor for any changes in your node.js application and automatically restart the server - perfect for development
To use nodemon:
$ npm install nodemon -g
$ nodemon app.js
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What does enctype='multipart/form-data' mean?
What does enctype='multipart/form-data' mean in an HTML form and when should we use it?
9 Answers
...
How to execute a Ruby script in Terminal?
...set everything up that I need on my Mac (Ruby, Rails, Homebrew, Git, etc), and I've even written a small program. Now, how do I execute it in Terminal? I wrote the program in Redcar and saved it as a .rb, but I don't know how to execute it through Terminal. I want to run the program and see if it ac...
How does the const constructor actually work?
...calized" instance.
That is, all constant expressions begin canonicalized, and later these "canonicalized" symbols are used to recognize equivalence of these constants.
Canonicalization:
A process for converting data that has more than one possible representation into a "standard" canonical repres...
C#: why sign an assembly?
...mblies to be signed with the same key.
Is signing assemblies necessary and what would be wrong with not signing it?
No, it is not necessary but it is a mechanism allowing you to ensure the authenticity of an assembly. It allows you to ensure that an assembly hasn't been tampered with and indee...
If string is empty then return some default value
Often I need to check if some value is blank and write that "No data present" like that:
6 Answers
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What is the PostgreSQL equivalent for ISNULL()
...ited Jan 14 '12 at 2:28
Erwin Brandstetter
439k9696 gold badges809809 silver badges969969 bronze badges
answered Feb 6 '10 at 20:02
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