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Adding a column to an existing table in a Rails migration
...ontaining line:
add_column :users, email, string
Then do a rake db:migrate and it'll run the new migration, creating the new column.
If you have not yet run the original migration you can just edit it, like you're trying to do. Your migration code is almost perfect: you just need to remove the add_...
How to get “wc -l” to print just the number of lines without file name?
outputs number of lines and file name.
9 Answers
9
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What is an xs:NCName type and when should it be used?
I ran one of my xml files through a schema generator and everything generated was what was expected, with the exception of one node:
...
Change old commit message on Git
...
It says:
When you save and exit the editor, it will rewind you back to that last commit in that list and drop you on the command line with the following message:
$ git rebase -i HEAD~3
Stopped at 7482e0d... updated the gemspec to hopefully work be...
64-bit version of Boost for 64-bit windows
...As a longer answer, here are my build notes for having VS .NET 2008 32-bit and 64-bit boost libraries in the same hierarchy (which is I suspect a common use case):
Build the win32 binaries
bjam --toolset=msvc-9.0 --build-type=complete stage
Create the directory lib\win32
Move the contents of sta...
Frontend tool to manage H2 database [closed]
...
I like SQuirreL SQL Client, and NetBeans is very useful; but more often, I just fire up the built-in org.h2.tools.Server and browse port 8082:
$ java -cp /opt/h2/bin/h2.jar org.h2.tools.Server -help
Starts the H2 Console (web-) server, TCP, and PG ser...
Show space, tab, CRLF characters in editor of Visual Studio
...ed > View White Space. The keyboard shortcut is CTRL+R, CTRL+W. The command is called Edit.ViewWhiteSpace.
It works in all Visual Studio versions at least since Visual Studio 2010, the current one being Visual Studio 2019 (at time of writing). In Visual Studio 2013, you can also use CTRL+E, S or...
How to calculate the difference between two dates using PHP?
...s answer below
You can use strtotime() to convert two dates to unix time and then calculate the number of seconds between them. From this it's rather easy to calculate different time periods.
$date1 = "2007-03-24";
$date2 = "2009-06-26";
$diff = abs(strtotime($date2) - strtotime($date1));
$year...
List Git aliases
... list of my git aliases, i.e., something analogous to the bash alias command?
16 Answers
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How can I inspect disappearing element in a browser?
...element that contains the disappearing element. Right click on the element and apply "Break on... > Subtree Modifications." This will throw a debugger pause before the element disappears, which will allow you to interact with the element in a paused state.
Update Oct 22 2019: with the release of...