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What is the optimal length for an email address in a database?
...
Especially if you want the email field to have a unique constraint; under INNODB and utf8 varchar(254) is small enough (less than 767bytes) to have a unique constraint and varchar(300) is not.
– Autonomy
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How to use dashes in HTML-5 data-* attributes in ASP.NET MVC
...an underscore.
For example:
@Html.TextBoxFor(vm => vm.City, new { data_bind = "foo" })
will render this in MVC 3:
<input data-bind="foo" id="City" name="City" type="text" value="" />
If you're still using an older version of MVC, you can mimic what MVC 3 is doing by creating this sta...
Why have header files and .cpp files? [closed]
...dencies so that code that uses the header doesn't necessarily need to know all the details of the implementation and any other classes/headers needed only for that. This will reduce compilation times and also the amount of recompilation needed when something in the implementation changes.
It's not ...
How to detect internet speed in JavaScript?
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Well, this is 2017 so you now have Network Information API (albeit with a limited support across browsers as of now) to get some sort of estimate downlink speed information:
navigator.connection.downlink
This is effective bandwidth estimate in Mbits per sec. The browser makes ...
Apache not starting on MAMP Pro
.... Go to bin -> apache2 -> bin.
Then rename the file from envvars to _envvars.
I also came across another problem of it not working correctly. Make sure the ports are Apache defaults, NOT MAMP defaults (port 80 etc). If it works straight away, this should not apply to you.
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HAXM 安装/启动失败？ - App Inventor 2 离线版 - 清泛IT社区，为创新赋能！
报错如下：
emulator: Android emulator version 30.3.5.0 (build_id 7033400) (CL:N/A)
127.0.0.1 - - [01/Apr/2025 16:55:37] "GET /echeck/ HTTP/1.1" 200 39
handleCpuAcceleration: feature check for hvf
emulator: ERROR: x86_64 emulation currently requires hardware acceleration!
CPU accel...
Python add item to the tuple
... @SIslam Without the comma, it will just be interpreted as brackets usually used to get around the order of precedence: (a+b)*c
– Joseph Young
Feb 25 '16 at 5:54
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delegate keyword vs. lambda notation
... If you specify an anonymous method without specifying a parameter list at all it is compatible with any delegate type returning void and without any out parameters. Armed with this knowledge, we should be able to construct two overloads to make the expressions completely unambiguous but very differ...
What is TypeScript and why would I use it in place of JavaScript? [closed]
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I originally wrote this answer when TypeScript was still
hot-off-the-presses. Five years later, this is an OK overview, but look
at Lodewijk's answer below for more depth
1000ft view...
TypeScript is a superset of JavaScript ...
get size of json object
... check the size i.e. like that:
var data = {one : 1, two : 2, three : 3};
_.size(data);
//=> 3
_.keys(data);
//=> ["one", "two", "three"]
_.keys(data).length;
//=> 3
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