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Paperclip::Errors::MissingRequiredValidatorError with Rails 4
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Starting with Paperclip version 4.0, all attachments are required to include a content_type validation, a file_name validation, or to explicitly state that they're not going to have either.
Paperclip raises Paperclip::Errors::MissingRequiredValidatorError error if you d...
How do I temporarily disable triggers in PostgreSQL?
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This disables triggers for the current session.
To re-enable for the same session:
SET session_replication_role = DEFAULT;
Source: http://koo.fi/blog/2013/01/08/disable-postgresql-triggers-temporarily/
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Linux, Why can't I write even though I have group permissions?
...want to create a file in a directory owned by the staff group which I am a member of. Why can I not do this?
6 Answers
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How to position a DIV in a specific coordinates?
... and top edge respectively. It must have position: absolute;
var d = document.getElementById('yourDivId');
d.style.position = "absolute";
d.style.left = x_pos+'px';
d.style.top = y_pos+'px';
Or do it as a function so you can attach it to an event like onmousedown
function placeDiv(x_pos, y_pos)...
Java resource as file
...owever, I don't believe there's any way of "listing" the contents of an element of the classpath.
In some cases this may be simply impossible - for instance, a ClassLoader could generate data on the fly, based on what resource name it's asked for. If you look at the ClassLoader API (which is basica...
What scalability problems have you encountered using a NoSQL data store? [closed]
... release, the traceback-logger website wasn't responding anymore. We had some locking issues with the production db of our main site which was throwing exceptions nearly every request, as well as several other bugs, which we haven't explored during the testing stage. The server cluster of our main s...
What is the best way to insert source code examples into a Microsoft Word document?
I have to write some documents that will include source code examples. Some of the examples will be written from the IDE, and others would be written in place. My examples are primarily in Java.
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How to drop columns by name in a data frame
...her indexing or the subset function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operator in column indexation :
R> df[ , -which(names(df) %in% c("z","u")...
Why does CSS work with fake elements?
...y class, I was playing around and found out that CSS works with made-up elements.
19 Answers
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Core pool size vs maximum pool size in ThreadPoolExecutor
...re pool size is
5, max pool size is 10 and the queue is 100.
As requests come in,
threads will be created up to 5 and then tasks will be added to the
queue until it reaches 100. When the queue is full new threads will be
created up to maxPoolSize. Once all the threads are in use and the
queue is ful...