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Throw an error in a MySQL trigger
...e SIGNAL syntax to throw an exception:
signal sqlstate '45000' set message_text = 'My Error Message';
State 45000 is a generic state representing "unhandled user-defined exception".
Here is a more complete example of the approach:
delimiter //
use test//
create table trigger_test
(
id int...
Smart way to truncate long strings
...
Essentially, you check the length of the given string. If it's longer than a given length n, clip it to length n (substr or slice) and add html entity … (…) to the clipped string.
Such a method looks like
function tru...
How to delete items from a dictionary while iterating over it?
...--------------------------------------------------
Traceback (most recent call last):
File "<ipython console>", line 1, in <module>
RuntimeError: dictionary changed size during iteration
As stated in delnan's answer, deleting entries causes problems when the iterator tries to move on...
How to convert image to byte array
...ollows:
public static byte[] converterDemo(Image x)
{
ImageConverter _imageConverter = new ImageConverter();
byte[] xByte = (byte[])_imageConverter.ConvertTo(x, typeof(byte[]));
return xByte;
}
share
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Check if a value is an object in JavaScript
...o examine variable's properties, but it is not a bulletproof recipe (after all there's no recipe at all!) for checking whether it's an object, far from it. Since people tend to look for something to copy from here without doing any research, I'd highly recommend that they turn to the other, most upv...
How to change height of grouped UITableView header?
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Return CGFLOAT_MIN instead of 0 for your desired section height.
Returning 0 causes UITableView to use a default value. This is
undocumented behavior. If you return a very small number, you
effectively get a zero-height header.
S...
How to create a date object from string in javascript [duplicate]
...return a JS Date object, with a robust selection of methods available from __proto__. Demo in jsFiddle
– KyleMit
Apr 11 '17 at 19:19
4
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How to check if object has any properties in JavaScript?
...d Apr 20 '10 at 6:49
Daniel VassalloDaniel Vassallo
301k6666 gold badges475475 silver badges424424 bronze badges
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MySQL get the date n days ago as a timestamp
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DATE_SUB will do part of it depending on what you want
mysql> SELECT DATE_SUB(NOW(), INTERVAL 30 day);
2009-06-07 21:55:09
mysql> SELECT TIMESTAMP(DATE_SUB(NOW(), INTERVAL 30 day));
2009-06-07 21:55:09
mysql> SELECT U...
indexOf method in an object array?
... think to see the performance of this method vs. a simple for loop. Especially when you're running on a mobile platform with limited resources.
– Doug
Aug 17 '15 at 5:51
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