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When to add what indexes in a table in Rails
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Should I add "index" to all the foreign keys like "xxx_id"?
It would be better, because it accelerates the search in sorting in this column. And Foreign keys are something searched for a lot.
Since Version 5 of rails the index will be created aut...
Collections.emptyList() vs. new instance
...ntly.
In addition, emptyList() might not create a new object with each call.
Implementations of this method need not create a separate List object for each call. Using this method is likely to have comparable cost to using the like-named field. (Unlike this method, the field does not provide ...
Reduce git repository size
... do I reduce my repo size...it's about 10 MB, but the thing is Heroku only allows 50 MB and I'm no where near finished developing my app.
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Pushing a local branch up to GitHub
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If you are really lazy, you can push all local branches by simply using
git push --all
--all
Push all branches (i.e. refs under refs/heads/); cannot be used with
other <refspec>.
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What is eager loading?
...hing when asked. Classic example is when you multiply two matrices. You do all the calculations. That's eager loading;
Lazy loading: you only do a calculation when required. In the previous example, you don't do any calculations until you access an element of the result matrix; and
Over-eager loadin...
Filter git diff by type of change
...de) changed
U Unmerged
X Unknown
B have had their pairing Broken
* All-or-none
Any combination of the filter characters may be used.
When * (All-or-none) is added to the combination, all paths are
selected if there is any file that matches other criteria in the
comparison; ...
How to select first and last TD in a row?
...d:first-child,
tr td:last-child {
/* styles */
}
This should work in all major browsers, but IE7 has some problems when elements are added dynamically (and it won't work in IE6).
share
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impro...
Inline SVG in CSS
...possible. I just went to the standard specification and stated it was virtually impossible, which turned out to be a mistake (sort of)
– toniedzwiedz
May 26 '12 at 19:05
18
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XPath OR operator for different nodes
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All title nodes with zipcode or book node as parent:
Version 1:
//title[parent::zipcode|parent::book]
Version 2:
//bookstore/book/title|//bookstore/city/zipcode/title
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How to configure MongoDB Java driver MongoOptions for production use?
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Updated to 2.9 :
autoConnectRetry simply means the driver will automatically attempt to reconnect to the server(s) after unexpected disconnects. In production environments you usually want this set to true.
connectionsPerHost are the amount of physical connections a single Mongo instance (it's si...