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When to use “ON UPDATE CASCADE”
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It's true that if your primary key is just a identity value auto incremented, you would have no real use for ON UPDATE CASCADE.
However, let's say that your primary key is a 10 digit UPC bar code and because of expansion, you need to chang...
How do I check for nulls in an '==' operator overload without infinite recursion?
...e(foo1 == foo2);
public static bool operator ==(Foo foo1, Foo foo2) {
if (object.ReferenceEquals(null, foo1))
return object.ReferenceEquals(null, foo2);
return foo1.Equals(foo2);
}
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Requests — how to tell if you're getting a 404
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Look at the r.status_code attribute:
if r.status_code == 404:
# A 404 was issued.
Demo:
>>> import requests
>>> r = requests.get('http://httpbin.org/status/404')
>>> r.status_code
404
If you want requests to raise an exception...
Loop through all the files with a specific extension
I want to loop through each file in the current folder and check if it matches a specific extension. The code above doesn't work, do you know why?
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Padding is invalid and cannot be removed?
...t can't seem to find a solution or the reason why it's happening to my specific program. I have been using the example provided my msdn for encrypting and decrypting an XmlDocument using the Rijndael algorithm. The encryption works fine but when I try to decrypt, I get the following exception:
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Type List vs type ArrayList in Java [duplicate]
... translated into a LinkedList without affecting the rest of the codebase.
If one used ArrayList instead of List, it's hard to change the ArrayList implementation into a LinkedList one because ArrayList specific methods have been used in the codebase that would also require restructuring.
You can r...
Test for multiple cases in a switch, like an OR (||)
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I might as well clarify the point: Once a case has evaluated to true, that's it. No more cases are checked, just all the statements executed until the end: i.e. a "break;" instruction or if the switch is terminated.
– BeauC...
When and why JPA entities should implement Serializable interface?
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This usually happens if you mix HQL and native SQL queries. In HQL, Hibernate maps the types you pass in to whatever the DB understands. When you run native SQL, then you must do the mapping yourself. If you don't, then the default mapping is to ...
What does “default” mean after a class' function declaration?
... the compiler-generated version of that function, so you don't need to specify a body.
You can also use = delete to specify that you don't want the compiler to generate that function automatically.
With the introduction of move constructors and move assignment operators, the rules for when automat...
Check if string ends with one of the strings from a list
...t not why it cannot accept lists. Since they are both sequences, the only difference I can potentially see is that lists are mutable, while tuples are immutable. I may be wrong, but I can't see any other reason why that is explicitly stated.
– KymikoLoco
Jan 31...