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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...
Find the files existing in one directory but not in the other [closed]
...rison is to use find with md5sum, then a diff.
Example:
Use find to list all the files in the directory then calculate the md5 hash for each file and pipe it to a file:
find /dir1/ -type f -exec md5sum {} \; > dir1.txt
Do the same procedure to the another directory:
find /dir2/ -type f -exe...
How do I provide custom cast support for my class?
...ou want users to have to cast it or whether you want it to happen automagically. Generally, one direction will always work, that's where you use implicit, and the other direction can sometimes fail, that's where you use explicit.
The syntax is like this:
public static implicit operator dbInt64(Byt...
How do I determine the target architecture of static library (.a) on Mac OS X?
...cutable ppc
Example with archive:
logan:/Users/logan% file /usr/lib/libMallocDebug.a
/usr/lib/libMallocDebug.a: Mach-O universal binary with 2 architectures
/usr/lib/libMallocDebug.a (for architecture i386): current ar archive random library
/usr/lib/libMallocDebug.a (for architecture ppc): ...
How do I install an R package from source?
...nt me along this great tutorial on webscraping NYtimes with R . I would really love to try it. However, the first step is to installed a package called RJSONIO from source.
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error: ‘uint16_t’ does not name a type - C/C++ - 清泛网 - 专注C/C++及内核技术
...ght notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHA...
Installation Issue with matplotlib Python [duplicate]
I have issue after installing the matplotlib package unable to import matplotlib.pyplot as plt . Any suggestion will be greatly appreciate.
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Where does gcc look for C and C++ header files?
...stem header.
If you run gcc in verbose mode on such a source, it will list all the system include locations as it looks for the bogus header.
$ echo "#include <bogus.h>" > t.c; gcc -v t.c; rm t.c
[..]
#include "..." search starts here:
#include <...> search starts here:
/usr/local...
Allowed characters in Linux environment variable names
What characters are allowed in Linux environment variable names? My cursory search of man pages and the web did only produce information about how to work with variables, but not which names are allowed.
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Eclipse: Enable autocomplete / content assist
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If you would like to use autocomplete all the time without having to worry about hitting Ctrl + Spacebar or your own keyboard shortcut, you can make the following adjustment in the Eclipse preferences to trigger autocomplete simply by typing several different cha...