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The differences between .build, .create, and .create! and when should they be used?
...< 3.x
The most important part, however, is that these methods can be called through an association (has_many, etc.) to automatically link the two models.
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MySQL error: key specification without a key length
...h as VARCHAR(512) will force MySQL to auto-convert the VARCHAR(512) to a SMALLTEXT datatype, which subsequently fails with error 1170 on key length if the column is used as primary key or unique or non-unique index. To solve this problem, specify a figure less than 256 as the size for VARCHAR field....
.NET JIT potential error?
...di
00000012 push esi
00000013 mov ecx,ebx
00000015 call dword ptr ds:[00170210h] ; first unrolled call
0000001b push edi ; WRONG! does not increment oVec.y
0000001c push esi
0000001d mov ecx,ebx
0000001f ca...
Polymorphism with gson
...mmands. The command can be start, stop , some other type of command. Naturally I have polymorphism, and start/stop command inherit from command.
...
How to write asynchronous functions for Node.js
...difference is that they are not executed immediately but passed around as callbacks.
How should I implement error event handling correctly
Generally API's give you a callback with an err as the first argument. For example
database.query('something', function(err, result) {
if (err) handle(e...
When should I use the assets as opposed to raw resources in Android?
...older.
Since raw is a subfolder of Resources (res), Android will
automatically generate an ID for any file located inside it. This
ID is then stored in the R class that will act as a reference to
a file, meaning it can be easily accessed from other Android classes
and methods and even in Android XM...
How to vertically align elements in ?
...horizontal <ul> and I need to center each <li> in it vertically. My markup is below. Each <li> has a border, and I need the items as well as their contents to be in the middle vertically. Please help; I am new to CSS.
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Converting PKCS#12 certificate into PEM using OpenSSL
... understand it as I am going to use it in future (to simplify my solution calling openssh as command)
– Jan Vlcinsky
May 8 '14 at 21:40
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IE7 does not understand display: inline-block
...lay: inline;
zoom: 1;
By default, IE7 only supports inline-block on naturally inline elements (Quirksmode Compatibility Table), so you only need this hack for other elements.
zoom: 1 is there to trigger hasLayout behaviour, and we use the star property hack for setting the display to inline only...
Is double square brackets [[ ]] preferable over single square brackets [ ] in Bash?
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[[ has fewer surprises and is generally safer to use. But it is not portable - POSIX doesn't specify what it does and only some shells support it (beside bash, I heard ksh supports it too). For example, you can do
[[ -e $b ]]
to test whether a file exists....