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Why does C++ require a user-provided default constructor to default-construct a const object?
...of T would invoke a user-provided constructor
of T (not inherited from a base class) or if
each direct non-variant non-static data member M of T has a default member initializer or, if M is of class type X (or array thereof), X
is const-default-constructible,
if T is a union with at le...
Rails 4 multiple image or file upload using carrierwave
...avatar:string
rake db:migrate
In post.rb
class Post < ActiveRecord::Base
has_many :post_attachments
accepts_nested_attributes_for :post_attachments
end
In post_attachment.rb
class PostAttachment < ActiveRecord::Base
mount_uploader :avatar, AvatarUploader
belongs_to :post
end...
Is unsigned integer subtraction defined behavior?
...n the two expressions we are discussing is performed in type unsigned int, based on the operand types. The result of the addition is unsigned int. Then that result is implicitly converted to the type required in context, a conversion which fails because the value is not representable in the new ty...
Can you create nested WITH clauses for Common Table Expressions?
...s a recursive query:
WITH y
AS
(
SELECT x, y, z
FROM MyTable
WHERE [base_condition]
UNION ALL
SELECT x, y, z
FROM MyTable M
INNER JOIN y ON M.[some_other_condition] = y.[some_other_condition]
)
SELECT *
FROM y
You may not need this functionality. I've done the following just to o...
Removing duplicate objects with Underscore for Javascript
...
If you're looking to remove duplicates based on an id you could do something like this:
var res = [
{id: 1, content: 'heeey'},
{id: 2, content: 'woah'},
{id: 1, content:'foo'},
{id: 1, content: 'heeey'},
];
var uniques = _.map(_.groupBy(res,function(doc)...
Is there a job scheduler library for node.js? [closed]
...
agenda is based on node-cron with a persisten layer (mongo). so the answer above is better.
– drdrej
Feb 6 '14 at 14:57
...
Difference between Observer, Pub/Sub, and Data Binding
...the functions stored in that array.
If we want to group observers handlers based on different events. We just need to modify that observersList to an Object like
var events = {
"event1": [handler1, handler2],
"event2": [handler3]
}
see this pubsub example for details.
and people call this v...
How to debug a maven goal with intellij idea?
...a negative score, it did help me fix the issue I had (how to debug a maven-based project in IntelliJ), and when "Googling" the issue it led me to this page.
– gbmhunter
Oct 17 '16 at 21:31
...
What is a 'multi-part identifier' and why can't it be bound?
I continually get these errors when I try to update tables based on another table. I end up rewriting the query, change the order of joins, change some groupings and then it eventually works, but I just don't quite get it.
...
Python Empty Generator Function
... the same thing.
It's a subtle difference, but I honestly think the yield-based functions are more readable and maintainable.
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