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Difference between Destroy and Delete
...ary key, and no callbacks are executed.
To enforce the object's before_destroy and after_destroy callbacks or any :dependent association options, use #destroy.
ActiveRecord::Persistence.destroy
Deletes the record in the database and freezes this instance to reflect that no changes should b...
ActiveRecord: size vs count
...e a new record without going through the relation, i.e. Comment.create(post_id: post.id), your post.comments.size will not be up to date, while post.comments.count will. So just be careful.
– mrbrdo
Mar 31 '13 at 19:52
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What would be C++ limitations compared C language? [closed]
...ary subset of C++. C is not a subset of C++ at all.
This is valid C:
foo_t* foo = malloc ( sizeof(foo_t) );
To make it compile as C++ you have to write:
foo_t* foo = static_cast<foo_t*>( malloc ( sizeof(foo_t) ) );
which isn't valid C any more. (you could use the C-style cast, it which...
VC MFC工具栏(CToolBar)控件 - C/C++ - 清泛网 - 专注C/C++及内核技术
...钮吧，首先在对应话类里添加一个按钮类成员变量CButton m_Button;
然后在对话框编辑区里给对话框添加一个按钮控件（单击这个按钮创建按钮控件）,然后添加这个按钮控件单击消息处理函数，并在函数添加以下语句：
RECT ButtonR...
What is a semaphore?
...interestingly it has already been used: albahari.com/threading/part2.aspx#_Semaphore
– Igor Brejc
Mar 27 '15 at 8:50
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TCP vs UDP on video stream
...occer-fans and the internet itself is against me so I figure it's my loss ^_^
– Alxandr
May 31 '11 at 12:46
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Percentage Height HTML 5/CSS
... edited Feb 18 '17 at 5:54
Web_Designer
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answered Oct 25 '09 at 21:15
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When do you use map vs flatMap in RxJava?
...ten" this observable of observables (you might start to see where the name _flat_Map comes from). RxJava provides a few ways to flatten observables and for sake of simplicity lets assume merge is what we want. Merge basically takes a bunch of observables and emits whenever any of them emits. (Lots o...
How do I append text to a file?
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better sudo rm -r / than sudo rm -rf /! ^_^ Is there a flag that would ask for confirmation before overwriting the contents of an existing file with >? Aliasing that to always use such a flag seems like it would be a good idea.
– sixty4bit
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Spring Boot application as a Service
...app
OR
sudo ln -s ~/myproject/build/libs/myapp-1.0.jar /etc/init.d/myapp_servicename
After that you can do the usual
/etc/init.d/myapp start
Then setup a link in whichever runlevel you want the app to start/stop in on boot if so desired.
As a systemd service
To run a Spring Boot applica...