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Can a foreign key be NULL and/or duplicate?
...0.
2 - Yes, as long as it's not a UNIQUE constraint or linked to a unique index.
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How to use the ProGuard in Android Studio?
... in proguard-rule.txt see some examples over here proguard.sourceforge.net/index.html#manual/examples.html
– pyus13
Jan 2 '14 at 17:09
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Exclude folder from search but not from the project list
...lem. If your project contains a /vendor directory, this will help speed up indexing in PHPStorm since it's ignored.
Right click on any folder to bring up the following options.
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How to read the mode field of git-ls-tree's output
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From the Git index-format.txt file, regarding the mode:
32-bit mode, split into (high to low bits)
4-bit object type
valid values in binary are 1000 (regular file), 1010 (symbolic link)
and 1110 (gitlink)
3-bit unus...
How to remove a field from params[:something]
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format.html { redirect_to(:controller => :shopping, :action => :index) }
else
format.html
end
end
this will remove params from the url
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What is the meaning of the prefix N in T-SQL statements and when should I use it?
... it does the other way then performance will get hurt because the column's index (if available) wont be used.
2. Character set:
If the column is of type nvarchar or nchar, then always use the prefix N while specifying the character string in the WHERE criteria/UPDATE/INSERT clause. If you do not d...
SSL certificate rejected trying to access GitHub over HTTPS behind firewall
...it to individual certificates put them to /usr/ssl/certs (your CApath) and index them.
Here is how to do it. With cygwin setup.exe install curl and openssl packages
execute:
$ cd /usr/ssl/certs
$ curl http://curl.haxx.se/ca/cacert.pem |
awk '{print > "cert" (1+n) ".pem"} /-----END CERTIFICAT...
Exotic architectures the standards committees care about
...int registers spilled to memory at the C compiler's whim. blog.frama-c.com/index.php?post/2011/03/03/cosine-for-real
– Pascal Cuoq
Aug 8 '11 at 17:18
2
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What is better, adjacency lists or adjacency matrices for graph problems in C++?
...y exists you can check for the existence of an edge in constant time using indexes. However, neighbour lookup takes O(n) since you need to check all possible neighbours.
The obvious space drawback is that for sparse graphs a lot of padding is added. See the memory discussion above for more informati...
Position Absolute + Scrolling
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top: 20px;
right: 50px;
height: 10px;
width: 600px;
z-index: 1000;
}
And in the HTML
<body>
<div id="mess"></div>
<div id="data">
Much content goes here.
</div>
</body>
When #data becomes longer tha the sceen, #mess ke...