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Want to find records with no associated records in Rails
...).where( :friends => { :person_id => nil } )
For the hmt it's basically the same thing, you rely on the fact that a person with no friends will also have no contacts:
Person.includes(:contacts).where( :contacts => { :person_id => nil } )
Update
Got a question about has_one in the c...
What are '$$' used for in PL/pgSQL
...c to function definitions. It can be used to replace single quotes practically anywhere in SQL scripts.
The body of a function happens to be a string literal which has to be enclosed in single quotes. Dollar-quoting is a PostgreSQL-specific substitute for single quotes to avoid quoting issues insi...
Best practices for overriding isEqual: and hash
...ly attributed to Dan Bernstein or Chris Torek. That older algorithm originally floated around on Usenet, and certain attribution is difficult. For example, there is some interesting commentary in this Apache code (search for their names) that references the original source.
Bottom line is, this i...
Eclipse interface icons very small on high resolution screen in Windows 8.1
...rious icons and buttons in the Eclipse (Kepler) interface are very, very small on a laptop with a 3200x1800px screen. The red error decoration that appears to indicate errors on files is difficult to see unless my nose a few cm from the screen.
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What does '
...
It's a shorthand for this:
<?php echo $a; ?>
They're called short tags; see example #2 in the documentation.
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How do I create a custom Error in JavaScript?
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I'm still a bit lost in all those prototype things. Why in your example you assign name to this.name and not to NotImplementedError.prototype.name? Can you answer please, it's crucial for my understanding :)
– jayarjo
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Better to 'try' something and catch the exception or test if it's possible first to avoid an excepti
...est option when the index is probably in the list and the IndexError is usually not raised. This way you avoid the need for an extra lookup by if index < len(my_list).
Python encourages the use of exceptions, which you handle is a phrase from Dive Into Python. Your example not only handles the e...
What does it mean when a CSS rule is grayed out in Chrome's element inspector?
... selected DOM node.
I guess, for the sake of completeness, dev tools shows all the rules from that set, whether they are applied or not.
In the case where a rule is applied to the currently selected element due to inheritance (i.e. the rule was applied to an ancestor, and the selected element inher...
How to POST raw whole JSON in the body of a Retrofit request?
...String foo, String bar) {
this.foo = foo;
this.bar = bar;
}
}
Calling with:
FooResponse = foo.postJson(new FooRequest("kit", "kat"));
Will yield the following body:
{"foo":"kit","bar":"kat"}
The Gson docs have much more on how object serialization works.
Now, if you really really ...
Re-enabling window.alert in Chrome
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Note that you must close all the tabs of the same domain where you opted out of that alert option.
– Miguel
May 4 '17 at 10:36
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