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Transaction isolation levels relation with locks on table
...(yes, two tables can be logically but not physically related in real-world apps =\).
READ COMMITTED - lock on committed data. You can read the data that was only committed. This means A writes data and B can't read the data saved by A until A executes a commit. The problem here is that C can update ...
Mongoose, Select a specific field with find
...
The _id field is always present unless you explicitly exclude it. Do so using the - syntax:
exports.someValue = function(req, res, next) {
//query with mongoose
var query = dbSchemas.SomeValue.find({}).select('name -_id'...
Understanding Python super() with __init__() methods [duplicate]
...ady.
Note that the syntax changed in Python 3.0: you can just say super().__init__() instead of super(ChildB, self).__init__() which IMO is quite a bit nicer. The standard docs also refer to a guide to using super() which is quite explanatory.
...
Python hashable dicts
...another dictionary for obvious reasons.
class hashabledict(dict):
def __hash__(self):
return hash(tuple(sorted(self.items())))
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How to create REST URLs without verbs?
...ruggling to determine how to design restful URLs. I'm all for the restful approach of using URLs with nouns and not verbs don't understand how to do this.
...
How to read a single character from the user?
...Windows, Linux and OSX: http://code.activestate.com/recipes/134892/
class _Getch:
"""Gets a single character from standard input. Does not echo to the
screen."""
def __init__(self):
try:
self.impl = _GetchWindows()
except ImportError:
self.impl = _Ge...
How to measure time in milliseconds using ANSI C?
...on many systems.
You can use this function like this:
struct timeval tval_before, tval_after, tval_result;
gettimeofday(&tval_before, NULL);
// Some code you want to time, for example:
sleep(1);
gettimeofday(&tval_after, NULL);
timersub(&tval_after, &tval_before, &tval_resu...
Is there a range class in C++11 for use with range based for loops?
...C++ standard library does not have one, but Boost.Range has boost::counting_range, which certainly qualifies. You could also use boost::irange, which is a bit more focused in scope.
C++20's range library will allow you to do this via view::iota(start, end).
...
How does functools partial do what it does?
...g like this (apart from keyword args support etc):
def partial(func, *part_args):
def wrapper(*extra_args):
args = list(part_args)
args.extend(extra_args)
return func(*args)
return wrapper
So, by calling partial(sum2, 4) you create a new function (a callable, to b...
Understanding garbage collection in .NET
...top the GC from being to over-eager with collecting a reference, that can happen in interop scenarios where a reference is passed to unmanaged code. The garbage collector cannot see such references being used by such code since it wasn't compiled by the jitter so doesn't have the table that says wh...