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How to rollback a specific migration?
...e error in the original post)
rake db:migrate VERSION=20100905201547
In order to rollback ONLY ONE specific migration (OUT OF ORDER) use:
rake db:migrate:down VERSION=20100905201547
Note that this will NOT rollback any interceding migrations -- only the one listed. If that is not what you inte...
PostgreSQL: Difference between text and varchar (character varying)
...T count(*) FROM (
SELECT substring(f,1,1) || f FROM test WHERE f<'a0' ORDER BY 1 LIMIT 80000
) t;
... And use EXPLAIN ANALYZE.
UPDATED AGAIN 2018 (pg10)
little edit to add 2018's results and reinforce recommendations.
Results in 2016 and 2018
My results, after average, in many machines...
Where and how is the _ViewStart.cshtml layout file linked?
...ws" folder that you might need it. If you add a custom RazorViewEngine in order to organize views into other folders, you have to include the file in the root of those alternate view folders as well. For example, I moved all the Inspinia template views into a folder and ran this in the view engine...
namedtuple and default values for optional keyword arguments
...(Node._fields)
>>> Node()
Node(val=None, left=None, right=None)
Order
In all versions of Python, if you set fewer default values than exist in the namedtuple, the defaults are applied to the rightmost parameters. This allows you to keep some arguments as required arguments.
>>>...
Removing duplicate objects with Underscore for Javascript
... array of strings. Also, if you add b values to the uniques and invert the order of a/b they are no longer considered unique by your function. (e.g. `"{\"a\":\"1\",\"b\":2}" != "{\"b\":2,\"a\":\"1\"}") Maybe im missing something, but shouldn't the result at least be useful? Here is a jsbin to illust...
Export specific rows from a PostgreSQL table as INSERT SQL script
...
Take care that the order of the columns you SELECT matches the order of the columns in the destination database. If it doesn't, this could fail, or worse, succeed but insert bad data.
– Nathan Wallace
Jul ...
Disable output buffering
...
A straight-forward way of using the flush keyword argument of Python 3 in order to always have unbuffered output is:
import functools
print = functools.partial(print, flush=True)
afterwards, print will always flush the output directly (except flush=False is given).
Note, (a) that this answers t...
ANTLR: Is there a simple example?
...
Highly active question. Earn 10 reputation in order to answer this question. The reputation requirement helps protect this question from spam and non-answer activity.
...
how to show alternate image if source image is not found? (onerror working in IE but not in mozilla)
... found" onerror="this.onerror=null;this.src='imagefound.gif';" />
By calling this.onerror=null it will remove the onerror then try to get the alternate image.
NEW
I would like to add a jQuery way, if this can help anyone.
<script>
$(document).ready(function()
{
$(".backup_picture"...
Sorting 1 million 8-decimal-digit numbers with 1 MB of RAM
...epeat. Once VALUE reaches zero you should have transmitted all integers in order from largest to smallest to the destination, and have only used about 47 bits of RAM for the two persistent variables (and whatever small amount you need for the temporary values).
I know this is horrible, and I know t...