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Ruby on Rails Callback, what is difference between :before_save and :before_create?
Could you explain in detail what the :before_save and :before_create Ruby on Rails callbacks are, and what they have to do with Rails validations? Does validation occur after :before_save or :before_create ?
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'float' vs. 'double' precision
... in C use IEEE 754 encoding.
This type of encoding uses a sign, a significand, and an exponent.
Because of this encoding, many numbers will have small changes to allow them to be stored.
Also, the number of significant digits can change slightly since it is a binary representation, not a decimal ...
Basic HTTP authentication with Node and Express 4
...n: 'yourlogin', password: 'yourpassword'} // change this
// parse login and password from headers
const b64auth = (req.headers.authorization || '').split(' ')[1] || ''
const [login, password] = Buffer.from(b64auth, 'base64').toString().split(':')
// Verify login and password are set and co...
In JavaScript, why is “0” equal to false, but when tested by 'if' it is not false by itself?
...you explicitly do "0" == false, both sides are being converted to numbers, and then the comparison is performed.
When you do: if ("0") console.log("ha"), the string value is being tested. Any non-empty string is true, while an empty string is false.
Equal (==)
If the two operands are not o...
Can someone explain Microsoft Unity?
...tern (we use it here), but I just can't really grasp this Unity thing yet, and I think it's the next step in our application design.
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Algorithm to randomly generate an aesthetically-pleasing color palette [closed]
I'm looking for a simple algorithm to generate a large number of random, aesthetically pleasing colors. So no crazy neon colors, colors reminiscent of feces, etc.
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How can I find out what FOREIGN KEY constraint references a table in SQL Server?
..._object_id) = 'YourTableName'
This way, you'll get the referencing table and column name.
Edited to use sys.tables instead of generic sys.objects as per comment suggestion.
Thanks, marc_s
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Is there a combination of “LIKE” and “IN” in SQL?
...ecause Full Text Search (FTS) is the recommended alternative.
Both Oracle and SQL Server FTS implementations support the CONTAINS keyword, but the syntax is still slightly different:
Oracle:
WHERE CONTAINS(t.something, 'bla OR foo OR batz', 1) > 0
SQL Server:
WHERE CONTAINS(t.something, '"b...
Browse the files created on a device by the iOS application I'm developing, on workstation?
...niser, go to your device's Summary tab. Find your application in the list, and click the disclosure triangle. Under it, you should see an icon saying "Application Data". Click the down pointing arrow to download the data, and it'll prompt you for somewhere to save it.
In Xcode 5, listed under your ...
IOException: read failed, socket might closed - Bluetooth on Android 4.3
...trange Exception when opening a BluetoothSocket on my Nexus 7 (2012), with Android 4.3 (Build JWR66Y, I guess the second 4.3 update). I have seen some related postings (e.g. https://stackoverflow.com/questions/13648373/bluetoothsocket-connect-throwing-exception-read-failed ), but none seems to prov...