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App Inventor 2 KIO4_Base64 拓展，更强大的图像Base64编解码工具，解码后...
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Set value to NULL in MySQL
I want a value to be set to NULL if nothing is put into the text box in the form I'm submitting. How can I make this happen?
I've tried inserting 'NULL' but this just adds the word NULL into the field.
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Removing first x characters from string?
How might one remove the first x characters from a string? For example, if one had a string lipsum , how would they remove the first 3 characters and get a result of sum ?
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std::function and std::bind: what are they, and when should they be used?
... to use them with std algorithms, but I haven't understood what Stroustrup says about them in the C++11 FAQ .
4 Answers
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Mysql ibdata 丢失或损坏如何通过frm&ibd 恢复数据 - 更多技术 - 清泛网 - ...
...，这个方法不能恢复你的数据。my.ini的设置为 innodb_file_per_table = 1。
参考 http://blog.chinaunix.net/uid-24111901-id-2627876.html
1、找回表结构，如果表结构没有丢失直接到下一步
a、先创建一个数据库，这个数据库必须是没有表和任何...
Convert light frequency to RGB?
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Here's a detailed explanation of the entire conversion process: http://www.fourmilab.ch/documents/specrend/. Source code included!
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What's the difference between event.stopPropagation and event.preventDefault?
...m to be doing the same thing...
Is one modern and one old? Or are they supported by different browsers?
7 Answers
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Undo scaffolding in Rails
... already run the migrations generated by the scaffold command, you have to perform a rollback first.
rake db:rollback
You can create scaffolding using:
rails generate scaffold MyFoo
(or similar), and you can destroy/undo it using
rails destroy scaffold MyFoo
That will delete all the files...
Remove plot axis values
...f there is a way to get rid of axis values, either the x-axis or y-axis respectively, in an r-plot graph.
5 Answers
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Abusing the algebra of algebraic data types - why does this work?
The 'algebraic' expression for algebraic data types looks very suggestive to someone with a background in mathematics. Let me try to explain what I mean.
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