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How to set a default value for a datetime column to record creation time in a migration?
...::Migration[5.0]
def change
create_table :posts do |t|
t.datetime :modified_at, default: -> { 'CURRENT_TIMESTAMP' }
t.timestamps
end
end
end
See discussion at https://github.com/rails/rails/issues/27077 and answer there by prathamesh-sonpatki
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Keep file in a Git repo, but don't track changes
...want to be tracked and use the following command:
git update-index --assume-unchanged FILE_NAME
and if you want to track the changes again use this command:
git update-index --no-assume-unchanged FILE_NAME
git-update-index documentation
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Direct casting vs 'as' operator?
...- it's simple and straightforward. I tend to almost never use 2 since if something is not the right type, I usually expect an exception to occur. I have only seen a need for this return-null type of functionality with badly designed libraries which use error codes (e.g. return null = error, instead ...
How to identify server IP address in PHP
...
No. On some shared hosts this returns ::1
– TheRealChx101
Aug 2 '14 at 6:18
3
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Skip certain tables with mysqldump
...ou can use the --ignore-table option. So you could do
mysqldump -u USERNAME -pPASSWORD DATABASE --ignore-table=DATABASE.table1 > database.sql
There is no whitespace after -p (this is not a typo).
If you want to ignore multiple tables you can use a simple script like this
#!/bin/bash
PASSWOR...
What is Model in ModelAndView from Spring MVC?
...h of properties.
Example 1
If you have...
return new ModelAndView("welcomePage","WelcomeMessage","Welcome!");
... then in your jsp, to display the message, you will do:-
Hello Stranger! ${WelcomeMessage} // displays Hello Stranger! Welcome!
Example 2
If you have...
MyBean bean = new MyBean...
uint8_t can't be printed with cout
...he blank actually.
You have to convert aa to unsigned int to output the numeric value, since ostream& operator<<(ostream&, unsigned char) tries to output the visible character value.
uint8_t aa=5;
cout << "value is " << unsigned(aa) << endl;
...
How do I run a Node.js application as its own process?
...
2016 answer: nearly every Linux distribution comes with systemd, which means forever, monit, PM2, etc. are no longer necessary - your OS already handles these tasks.
Make a myapp.service file (replacing 'myapp' with your app's name, obviously):
[Unit]
Description=My app...
connecting to MySQL from the command line
How can you connect to MySQL from the command line in a Mac? (i.e. show me the code)
6 Answers
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How does the HyperLogLog algorithm work?
I've been learning about different algorithms in my spare time recently, and one that I came across which appears to be very interesting is called the HyperLogLog algorithm - which estimates how many unique items are in a list.
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