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Adding :default => true to boolean in existing Rails column
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change_column is a method of ActiveRecord::Migration, so you can't call it like that in the console.
If you want to add a default value for this column, create a new migration:
rails g migration add_default_value_to_show_attribute
Then in the migration created:
# That's the more generic way t...
Using IQueryable with Linq
...t;T>. Say, for example, you have a Products table, and you want to get all of the products whose cost is >$25.
If you do:
IEnumerable<Product> products = myORM.GetProducts();
var productsOver25 = products.Where(p => p.Cost >= 25.00);
What happens here, is the database loads ...
What are transparent comparators?
..., not by default.
The new member function template overloads of find etc. allow you to use a type that is comparable with the container's key, instead of using the key type itself. See N3465 by Joaquín Mª López Muñoz for rationale and a detailed, carefully written proposal to add this feature....
psql: FATAL: role “postgres” does not exist
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432
NOTE: If you installed postgres using homebrew, see the comment from @user3402754 below.
Note...
Is it possible to use “/” in a filename?
...hould ever be done, but is there a way to use the slash character that normally separates directories within a filename in Linux?
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Hook up Raspberry Pi via Ethernet to laptop without router? [closed]
I'm working on a balloon project with a Raspberry Pi. When we potentially recover the Raspberry Pi, it will most likely be in a rural location and I'd like to turn off the Pi at that point safely.
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Given a DateTime object, how do I get an ISO 8601 date in string format?
...xt in a format that is only correct for local times. This can happen when calling DateTime.ToString using the 'z' format specifier, which will include a local time zone offset in the output."
– Tom Lianza
Nov 2 '10 at 4:59
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Start ssh-agent on login
...a remote Git repo pulling from Bitbucket.com using an SSH alias. I can manually start the ssh-agent on my server but I have to do this every time I login via SSH.
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Query grants for a table in postgres
How can I query all GRANTS granted to an object in postgres?
7 Answers
7
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Sleeping in a batch file
... a Windows box, I've needed to pause its execution for several seconds (usually in a test/wait loop, waiting for a process to start). At the time, the best solution I could find uses ping (I kid you not) to achieve the desired effect. I've found a better write-up of it here , which describes a call...