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delete_all vs destroy_all?
...he model class.
So instead of :
u = User.find_by_name('JohnBoy')
u.usage_indexes.destroy_all
You can do :
u = User.find_by_name('JohnBoy')
UsageIndex.destroy_all "user_id = #{u.id}"
The result is one query to destroy all the associated records
...
What does FETCH_HEAD in Git mean?
...it like doing git fetch without arguments (or git remote update), updating all your remote branches, then running git merge origin/<branch>, but using FETCH_HEAD internally instead to refer to whatever single ref was fetched, instead of needing to name things.
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Django database query: How to get object by id?
Django automatically creates an id field as primary key.
6 Answers
6
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Calling C/C++ from Python?
...e Boost Python Library is a framework for interfacing Python and
C++. It allows you to quickly and seamlessly expose C++ classes
functions and objects to Python, and vice-versa, using no special
tools -- just your C++ compiler. It is designed to wrap C++ interfaces
non-intrusively, so that y...
Is there a way to crack the password on an Excel VBA Project?
...y best to explain how it works - please excuse my English.
The VBE will call a system function to create the password dialog box.
If user enters the right password and click OK, this function returns 1. If user enters the wrong password or click Cancel, this function returns 0.
After the dialog bo...
Unique (non-repeating) random numbers in O(1)?
...ntegers with the values 0-1000 and set a variable, max, to the current max index of the array (starting with 1000). Pick a random number, r, between 0 and max, swap the number at the position r with the number at position max and return the number now at position max. Decrement max by 1 and conti...
Syntax for creating a two-dimensional array
...2][3] marks[2][4]
NOTE:
If you want to store n elements then the array index starts from zero and ends at n-1.
Another way of creating a two dimensional array is by declaring the array first and then allotting memory for it by using new operator.
int marks[][]; // declare marks array
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How to remove non-alphanumeric characters?
I need to remove all characters from a string which aren't in a-z A-Z 0-9 set or are not spaces.
9 Answers
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Java abstract interface
...blic void interfacing();
public abstract boolean interfacing(boolean really);
\___.__/
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'----> nor this, are necessary.
}
Interfaces and their methods are implicitly abstract and adding that modifier makes no difference.
Is there other rules tha...
window.onload vs document.onload
...►Example Project:
The code above is taken from this project's codebase (index.html and keyboarder.js).
For a list of event handlers of the window object, please refer to the MDN documentation.
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