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#1071 - Specified key was too long; max key length is 1000 bytes
...ing such long VARCHAR columns anyway, because the index will be very bulky and inefficient.
The best practice is to use prefix indexes so you're only indexing a left substring of the data. Most of your data will be a lot shorter than 255 characters anyway.
You can declare a prefix length per colu...
Check whether a string matches a regex in JS
...fails because numbers don't have a match member). I'd reccomend explicitly converting your number to a string if you want to use it with a regex (String(123) for example).
– Bronzdragon
Jan 20 '19 at 14:47
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Choice between vector::resize() and vector::reserve()
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The two functions do vastly different things!
The resize() method (and passing argument to constructor is equivalent to that) will insert or delete appropriate number of elements to the vector to make it given size (it has optional second argument to specify their value). It will affect the ...
How to programmatically take a screenshot on Android?
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Here is the code that allowed my screenshot to be stored on an SD card and used later for whatever your needs are:
First, you need to add a proper permission to save the file:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
And this is the code (running in a...
T-SQL: Using a CASE in an UPDATE statement to update certain columns depending on a condition
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I know this is a very old question and the problem is marked as fixed. However, if someone with a case like mine where the table have trigger for data logging on update events, this will cause problem. Both the columns will get the update and log will make use...
What tools to automatically inline CSS style to create email HTML code? [closed]
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Check the premailer.dialect.ca online converter or this Python script to do it.
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How to avoid “if” chains?
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You can use an && (logic AND):
if (executeStepA() && executeStepB() && executeStepC()){
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}
executeThisFunctionInAnyCase();
this will satisfy both of your requirements:
executeStep<X>() should evaluate only if the pre...
How to compare Lists in Unit Testing
...gave more detailed messages when it failed. "Different number of elements" and "Element at index 0 do not match" are slightly useless. What are they then?!
– Colonel Panic
May 15 '15 at 15:45
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How do lexical closures work?
.... This is exactly the problem, though - in this environment, i is mutated, and the closures all refer to the same i.
Here is the best solution I can come up with - create a function creater and invoke that instead. This will force different environments for each of the functions created, with a dif...
How does HashSet compare elements for equality?
..., it will find the hash code using IEqualityComparer<T>.GetHashCode, and store both the hash code and the element (after checking whether the element is already in the set, of course).
To look an element up, it will first use the IEqualityComparer<T>.GetHashCode to find the hash code, t...