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What is the optimal length for an email address in a database?
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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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find -exec with multiple commands
...e? this is failing: find ./* -exec grep -v 'COLD,' {} \; -exec egrep -i "my_string" {} \;
– rajeev
Jan 22 '13 at 16:08
53
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What's the difference between assignment operator and copy constructor?
...grants you for free, so it would not make much sense to implement them manually. If you have one of these two, it's likely that you are manually managing some resource. In that case, per The Rule of Three, you'll very likely also need the other one plus a destructor.)
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What is a word boundary in regex?
... be "identifier" characters (alnums and underscore), not as anything especially useful for English.
– hobbs
Aug 24 '09 at 21:02
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What is the difference between is_a and instanceof?
...ut PHP versions >= 5.3.9 now accept an optional third boolean argument $allow_string (defaults to false) to allow comparisons of string class names instead:
class MyBaseClass {}
class MyExtendingClass extends MyBaseClass {}
// Original behavior, evaluates to false.
is_a(MyExtendingClass::class,...
How can I detect the touch event of an UIImageView?
...cify images) over the UIImageView. Then attach whatever methods you want called to that.
You can use that technique for many cases where you really want some area of the screen to act as a button instead of messing with the Touch stuff.
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C# 通过代码安装、卸载、启动、停止服务 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...e)
{
try
{
IDictionary _SavedState = new Hashtable();
ServiceController service = new ServiceController(serviceName);
string dispName = string.Empty;
if (!ServiceIsExisted(serviceName, ref dispName...
Combine --user with --prefix error with setup.py install
...me workaround:
pip install --user --install-option="--prefix=" <package_name>
or
python setup.py install --user --prefix=
Note that there is no text (not even whitespace) after the =.
Do not forget the --user flag.
Installing multiple packages:
Create ~/.pydistutils.cfg (or equivalent...
bool to int conversion
... 1, 4>5 would evaluate to 0.
EDIT: Jens in the comment said, C99 has _Bool type. bool is a macro defined in stdbool.h header file. true and false are also macro defined in stdbool.h.
§7.16 from C99 says,
The macro bool expands to _Bool.
[..] true which expands to the integer constan...
Why C# fails to compare two object types with each other but VB doesn't?
..., as things like Option Compare can affect how text is compared.
Fundamentally the operators don't work the same way and aren't intended to work the same way.
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