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MySQL, update multiple tables with one query
...'blah';
To see what this is going to update, you can convert this into a select statement, e.g.:
SELECT t2.t1_id, t2.t3_id, t1.a, t2.b, t2.c AS t2_c, t3.c AS t3_c
FROM t1
INNER JOIN t2 ON t2.t1_id = t1.id
INNER JOIN t3 ON t2.t3_id = t3.id
WHERE t1.a = 'blah';
An example using the same tables as...
Removing all empty elements from a hash / YAML?
...mplementation is not recursive. As a curiosity, they implemented it using #select instead of #delete_if for performance reasons. See here for the benchmark.
In case you want to backport it to your Rails 3 app:
# config/initializers/rails4_backports.rb
class Hash
# as implemented in Rails 4
# ...
“File not found” when running new LibGDX project
...s using Android Studio or IntelliJ IDEA, you need to follow these steps:
Select Run -> Edit Configurations from the menu
In the "Working Directory:" text box, append "/android/assets" to the path.
Note that if you execute tasks with gradle, this is not an issue. The gradle.build files are con...
BIO与NIO、AIO的区别(这个容易理解) - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...IO是否完成，那么为什么说是阻塞的呢？因为此时是通过select系统调用来完成的，而select函数本身的实现方式是阻塞的，而采用select函数有个好处就是它可以同时监听多个文件句柄，从而提高系统的并发性！
异步非阻塞IO:在此...
Cannot use identity column key generation with ( TABLE_PER_CLASS )
...refer using 'TABLE' id generation strategy as it triggers lots of queries (select, insert, and update) and maintains locks to generate unique values for primary key. So what would be an alternate solution to this If we have a kinda big Inheritance scenario? It will certainly impact the performance a...
Convert seconds to Hour:Minute:Second
...ed to that of the TIME data type, which is from -838:59:59 to 838:59:59 :
SELECT SEC_TO_TIME(8525);
# 02:22:05
See: SEC_TO_TIME
Run the Demo
PostgreSQL example:
SELECT TO_CHAR('8525 second'::interval, 'HH24:MI:SS');
# 02:22:05
Run the Demo
...
jQuery Click fires twice when clicking on label
... This worked for me as i still wanted the radio button to be selected. I just didn't want the event handler do to everything twice.
– chovy
Dec 14 '13 at 1:50
1
...
How does `is_base_of` work?
...;B, D>&)
D* (Host<B, D>&)
This would mean that we can't select by constness anymore. In an ordinary overload resolution scenario, the call would now be ambiguous because normally the return type won't participate in overload resolution. For conversion functions, however, there is ...
Visual Studio retrieving an incorrect path to a project from somewhere
...Source Control menu or the workspace drop down in Source Control Explorer)
select edit for your workspace.
You should see, under working folders, a mapping for the source
control directory to the old/wrong project directory.
Select it and click remove.
Close VS and delete the suo file.
It still r...
EC2 Instance Cloning
...he easier way is through the web management console:
go to the instance
select the instance and click on instance action
create image
Once you have an image you can launch another cloned instance, data and all. :)
shar...