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Can a foreign key be NULL and/or duplicate?
...inition. Null by definition is not a value. Null means that we do not yet know what the value is.
Let me give you a real life example. Suppose you have a database that stores sales proposals. Suppose further that each proposal only has one sales person assigned and one client. So your proposal tab...
Partly JSON unmarshal into a map in Go
...t as value identifier, telling the Go server what kind of value it is. By knowing what type of value, I can then proceed to JSON unmarshal the value into the correct type of struct.
...
Preferred method to store PHP arrays (json_encode vs serialize)
...-8 characters to unicode escape sequences." No longer necessarily true: we now have JSON_UNESCAPED_UNICODE.
– TRiG
Nov 24 '12 at 17:01
32
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string c_str() vs. data()
...In C++11 onwards, both functions are required to be the same. i.e. data is now required to be null-terminated. According to cppreference: "The returned array is null-terminated, that is, data() and c_str() perform the same function."
...
PHP memory profiling
...
im trying to use qcachegrind now and don't understand what I'm looking at. I don't see memory numbers anywhere. How much memory does each variable take up? I want something that can trace the execution and show the memory at each point, and what varia...
Android List View Drag and Drop sort
...
I have been working on this for some time now. Tough to get right, and I don't claim I do, but I'm happy with it so far. My code and several demos can be found at
https://github.com/bauerca/drag-sort-listview
Its use is very similar to the TouchInterceptor (on wh...
100% Min Height CSS layout
...
Since it is no longer in the normal flow, padding-bottom of #content
now provides the space for the absolute #footer. This padding is
included in the scrolled height by default, so that the footer will
never overlap the above content.
Scale the text size a bit or resize your browser w...
python: Change the scripts working directory to the script's own directory
... into whatever directory your Python script is located, even if you don't know what directory that will be when you're writing your script. To do this, you can use the os.path functions:
import os
abspath = os.path.abspath(__file__)
dname = os.path.dirname(abspath)
os.chdir(dname)
This takes th...
How efficient is locking an unlocked mutex? What is the cost of a mutex?
... itself manages the scheduling and context switches, this makes sense. But now I have a rough imagination about what the mutex lock/unlock will do internally.
– Albert
Sep 6 '10 at 21:55
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How to check if object has any properties in JavaScript?
...ave any way to create non-enumerable properties.
However this has changed now with ECMAScript 5th Edition, and we are able to create non-enumerable, non-writable or non-deletable properties, so the above method can fail, e.g.:
var obj = {};
Object.defineProperty(obj, 'test', { value: 'testVal',
...