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Understanding :source option of has_one/has_many through of Rails
...'ve chosen to namespace the Dog::Breed, because we want to access Dog.find(123).breeds as a nice and convenient association.
Now, if we now want to create a has_many :dog_breeds, :through => :dogs association on Pet, we suddenly have a problem. Rails won't be able to find a :dog_breeds associati...
Is “double hashing” a password less secure than just hashing it once?
...use an ordered list of the most likely passwords. They start with "password123" and progress to less frequently used passwords.
Let's say an attackers list is long, with 10 billion candidates; suppose also that a desktop system can compute 1 million hashes per second. The attacker can test her who...
Listening for variable changes in JavaScript
...c.innerHTML = c.innerHTML + '<br />' + t;
}
// Demo
var myVar = 123;
Object.defineProperty(this, 'varWatch', {
get: function () { return myVar; },
set: function (v) {
myVar = v;
print('Value changed! New value: ' + v);
}
});
print(varWatch);
varWatch = 456;
pri...
Cast a Double Variable to Decimal
...hould use the M when declaring a new literal decimal value:
decimal dec = 123.45M;
(Without the M, 123.45 is treated as a double and will not compile.)
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Fastest way to check if a string is JSON in PHP?
...
$phone = '021234567'; var_dump(isJson($phone)); return true no! it should return false.
– vee
Jan 2 '14 at 17:12
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Difference between filter and filter_by in SQLAlchemy
...
Be careful when using .filter. a query like id=12345, query(users).filter(id == id) will not filter on users.id. Instead, it will evaluate id == id as True and return all users. You need to use .filter(users.id == id) (as demoed above). I made this mistake earlier today.
...
What is a method group in C#?
...) overload which takes a string parameter:
Func<string,string> fn = 123.ToString;
Console.WriteLine(fn("00000000"));
This example picks the ToString() overload which takes no parameters:
Func<string> fn = 123.ToString;
Console.WriteLine(fn());
...
How do I create a unique constraint that also allows nulls?
...et_AllowNull
UNIQUE (TicketID, TicketUnique);
If IssueID 1 has ticket 123, the UNIQUE constraint will be on values (123, NULL). If IssueID 2 has no ticket, it will be on (NULL, 2). Some thought will show that this constraint cannot be duplicated for any row in the table, and still allows multip...
Is JavaScript an untyped language?
...licit compiler interjection, the instruction will error during run-time.
"12345" * 1 === 12345 // string * number => number
Strongly typed means there is a compiler, and it wants you an explicit cast from string to integer.
(int) "12345" * 1 === 12345
In either case, some compiler's featur...
import module from string variable
...ike importlib.import_module("feature.email")
– Seanny123
Dec 6 '13 at 7:13
11
Finally, also remem...