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I need to generate uuid for my rails application. What are the options(gems) I have? [duplicate]
... the column.
Example in Rails 3 migration
execute <<-SQL
CREATE TABLE some_items (id uuid PRIMARY KEY DEFAULT uuid_generate_v1());
SQL
Might be a better way to do this in Rails 4.
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How is Math.Pow() implemented in .NET Framework?
...plemented in the CLR, written in C++. The just-in-time compiler consults a table with internally implemented methods and compiles the call to the C++ function directly.
Having a look at the code requires the source code for the CLR. You can get that from the SSCLI20 distribution. It was written arou...
grep using a character vector with multiple patterns
...attern = 'A1|A9|A6', x = myfile$Letter)
Or even more simply:
library(data.table)
myfile$Letter %like% 'A1|A9|A6'
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How to install mongoDB on windows?
...st imagine an SQL server or Oracle Db with entirely different rows in same table? Is it possible in our relational DB table? This is how mongo works. I will show you how we can do that…
First I will show you how the data will look in a relational DB.
For example consider an Employee table and a S...
brew install mysql on macOS
... like there is something wrong with the set up instructions or the initial tables that are being created. This is how I got mysqld running on my machine.
If the mysqld server is already running on your Mac, stop it first with:
launchctl unload -w ~/Library/LaunchAgents/com.mysql.mysqld.plist
Star...
Linear Regression and group by in R
...factor are your variables. Please keep in mind that Your.df must be a data.table class
– FraNut
Nov 17 '15 at 9:33
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Why switch is faster than if
...h switch the JVM loads the value to compare and iterates through the value table to find a match, which is faster in most cases.
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how to generate migration to make references polymorphic
I have a Products table and want to add a column:
4 Answers
4
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ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
...nit.d/mysqld stop
Start MySQL in safe mode
sudo mysqld_safe --skip-grant-tables &
Log into MySQL using root
mysql -uroot
Select the MySQL database to use
use mysql;
Reset the password
-- MySQL version < 5.7
update user set password=PASSWORD("mynewpassword") where User='root';
-- MySQ...
Fast permutation -> number -> permutation mapping algorithms
... brought down to n*log(n), see section 10.1.1
("The Lehmer code (inversion table)", p.232ff) of the fxtbook:
http://www.jjj.de/fxt/#fxtbook
skip to section 10.1.1.1 ("Computation with large arrays" p.235) for the fast method.
The (GPLed, C++) code is on the same web page.
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