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Check if a table exists in Rails
...? 'kittens'
In Rails 2, 3 & 4 the API is about tables.
# Listing of all tables and views
ActiveRecord::Base.connection.tables
# Checks for existence of kittens table/view (Kitten model)
ActiveRecord::Base.connection.table_exists? 'kittens'
Getting the status of migrations:
# Tells you all...
TCP: can two different sockets share a port?
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A server socket listens on a single port. All established client connections on that server are associated with that same listening port on the server side of the connection. An established connection is uniquely identified by the combination of client-side and serv...
Why Doesn't C# Allow Static Methods to Implement an Interface?
... public static void Bar() {}
}
This doesn't make sense to me, semantically. Methods specified on an interface should be there to specify the contract for interacting with an object. Static methods do not allow you to interact with an object - if you find yourself in the position where your im...
Cross Domain Form POSTing
I've seen articles and posts all over (including SO) on this topic, and the prevailing commentary is that same-origin policy prevents a form POST across domains. The only place I've seen someone suggest that same-origin policy does not apply to form posts, is here .
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When restoring a backup, how do I disconnect all active connections?
...ecificed DELAY, thereby giving user queries an opporunity to complete naturally.
– John Sansom
Jul 20 '09 at 16:02
2
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Is there a “previous sibling” selector?
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I found a way to style all previous siblings (opposite of ~) that may work depending on what you need.
Let's say you have a list of links and when hovering on one, all the previous ones should turn red. You can do it like this:
/* default lin...
How to keep keys/values in same order as declared?
...ry that I declared in a particular order and want to keep it in that order all the time. The keys/values can't really be kept in order based on their value, I just want it in the order that I declared it.
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How to install packages using pip according to the requirements.txt file from a local directory?
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This works for me:
$ pip install -r requirements.txt --no-index --find-links file:///tmp/packages
--no-index - Ignore package index (only looking at --find-links URLs instead).
-f, --find-links <URL> - If a URL or path to an html file, then par...
What's the purpose of the LEA instruction?
...ed to support high-level languages like Pascal and C, where arrays—especially arrays of ints or small structs—are common. Consider, for example, a struct representing (x, y) coordinates:
struct Point
{
int xcoord;
int ycoord;
};
Now imagine a statement like:
int y = points[i].ycoor...
Remove sensitive files and their commits from Git history
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For all practical purposes, the first thing you should be worried about is CHANGING YOUR PASSWORDS! It's not clear from your question whether your git repository is entirely local or whether you have a remote repository elsewhere...