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Installing PG gem on OS X - failure to build native extension
It seems many others have had problems installing the pg gem. None of the solutions posed for others have worked for me.
1...
What's wrong with nullable columns in composite primary keys?
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Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key containing NULL would not work.
Additonally, NULL is al...
Is git good with binary files?
...aningful diffs, or merge binary files in any way that could make sense. So all merges, rebases or cherrypicks involving a change to a binary file will involve you making a manual conflict resolution on that binary file.
You need to decide whether the binary file changes are rare enough that you can...
How do I speed up the gwt compiler?
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Let's start with the uncomfortable truth: GWT compiler performance is really lousy. You can use some hacks here and there, but you're not going to get significantly better performance.
A nice performance hack you can do is to compile for only specific browsers, by inserting the following line in...
In Python, if I return inside a “with” block, will the file still close?
...o that doesn't guarantee the call of a finally statement: "Note that exit handlers and finally clauses, etc., will not be executed."
– Rik Poggi
Mar 27 '12 at 7:55
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Can dplyr package be used for conditional mutating?
...and the conditions (except for the default value of NA at the end) are mutually exclusive, as is the case in the question, then we can use an arithmetic expression such that each term is multiplied by the desired result using na_if at the end to replace 0 with NA.
df %>%
mutate(g = 2 * (a == 2 ...
What is the 'new' keyword in JavaScript?
...n's external, accessible, prototype object (every function object automatically has a prototype property).
It makes the this variable point to the newly created object.
It executes the constructor function, using the newly created object whenever this is mentioned.
It returns the newly created objec...
Create unique constraint with null columns
...or may not be useful. In extreme situations it might even help to maintain all three indexes (the two partial ones and a total on top).
Aside: I advise not to use mixed case identifiers in PostgreSQL.
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Caching a jquery ajax response in javascript/browser
... return localCache.data[url];
},
set: function (url, cachedData, callback) {
localCache.remove(url);
localCache.data[url] = cachedData;
if ($.isFunction(callback)) callback(cachedData);
}
};
$(function () {
var url = '/echo/jsonp/';
$('#ajaxButton').clic...
How to see the changes between two commits without commits in-between?
...question, so I have no idea why it has so many upvotes. The OP is specifically asking how NOT to get the first command you give, and the second has nothing to do with anything.
– psusi
Sep 4 '15 at 17:51
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