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Best practices for in-app database migration for Sqlite
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I maintain an application that periodically needs to update a sqlite database and migrate old databases to the new schema and here's what I do:
For tracking the database version, I use the built in user-version variable that sqlite provides (sqlite does nothing w...
How can I match a string with a regex in Bash?
...ching in the second example. Inside [[ ]], the * is not expanded as it usually is, to match filenames in the current directory that match a pattern.Your example works, but it's really easy to over-generalize and mistakenly believe that * means to match anything in any context. It only works like t...
How to normalize a path in PowerShell?
...WINDOWS\system32\fred\frog\..\frag
With an absolute base, it is safe to call the .NET API GetFullPath:
[System.IO.Path]::GetFullPath((Join-Path (Join-Path (pwd) fred\frog) '..\frag'))
Which gives you the fully qualified path and with the .. removed:
C:\WINDOWS\system32\fred\frag
It's not com...
How to get rid of `deprecated conversion from string constant to ‘char*’` warnings in GCC?
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THIS IS HORRIBLY BAD PRACTICE, and I'm sad it got all those votes. Warnings are not there so that you ignore them. Warnings are there telling you "dude, you're doing something that could be wrong, be careful", and you should only suppress them when you wanna respond like "sh...
Using the HTML5 “required” attribute for a group of checkboxes?
... checked. Following is your html code (make sure that you add required for all the elements in the group.)
<input type="checkbox" name="option[]" id="option-1" value="option1" required/> Option 1
<input type="checkbox" name="option[]" id="option-2" value="option2" required/> Option 2
&l...
Why do C and C++ compilers allow array lengths in function signatures when they're never enforced?
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It is a quirk of the syntax for passing arrays to functions.
Actually it is not possible to pass an array in C. If you write syntax that looks like it should pass the array, what actually happens is that a pointer to the first element of the array is passed instead.
Since the pointer does...
What is the proper way to re-throw an exception in C#? [duplicate]
... ends on that statement and not at the real source of the exception.
Basically, it should be deemed a criminal offense to use "throw ex".
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What does the construct x = x || y mean?
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It means the title argument is optional. So if you call the method with no arguments it will use a default value of "Error".
It's shorthand for writing:
if (!title) {
title = "Error";
}
This kind of shorthand trick with boolean expressions is common in Perl too. With the...
Captured variable in a loop in C#
...ompiler is generating a class that represents the closure for your method call. It uses that single instance of the closure class for each iteration of the loop. The code looks something like this, which makes it easier to see why the bug happens:
void Main()
{
List<Func<int>> actio...
How to print the values of slices
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For a []string, you can use strings.Join():
s := []string{"foo", "bar", "baz"}
fmt.Println(strings.Join(s, ", "))
// output: foo, bar, baz
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