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How to create a unique index on a NULL column?
...k, and normalization usually involves the addition of several (non-entity) extra tables to establish relationships between the entities.
Let's work a basic example considering only one "unique nullable column", it's easy to expand it to more such columns.
Suppose we the information represented by ...
Invalidating JSON Web Tokens
...exists / is authorized to access the api endpoint. So you aren't doing any extra db queries by comparing the jwt token version number with the one on the user.
– DaftMonk
Jul 7 '14 at 5:58
...
Private virtual method in C++
...anup()s in the chain, the argument falls apart. Or are you recommending an extra virtual function for each descendant in the chain? Ick. Even Herb Sutter allowed protected virtual functions as a loophole in his guideline #3. Anyway, without some actual code you'll never convince me.
...
How to access the correct `this` inside a callback?
... that adds meaning, or some preceding and following information that gives extra meaning. The term "context" is used in ECMAScript to refer to execution context, which is all the parameters, scope, and this within the scope of some executing code.
This is shown in ECMA-262 section 10.4.2:
Set the T...
Should I implement __ne__ in terms of __eq__ in Python?
... work (assuming SQLAlchemy knows how to insert MyClassWithBadNE into a SQL string at all; this can be done with type adapters without MyClassWithBadNE having to cooperate at all), passing the expected proxy object to filter, while:
results = session.query(MyTable).filter(MyClassWithBadNE() != MyTa...
Qt events and signal/slots
...resents a new abstraction: a widget that acts like a button, but with some extra functionality. We added this functionality very conveniently:
Since we reimplemented a virtual, our implementation automatically became encapsulated in our class. If Qt's designers had made keyPressEvent a signal, we ...
Making 'git log' ignore changes for certain paths
...ath-match checks on individual paths under the directory would cause those extra paths to be filtered out, the only difference from using the wrong function was unnecessary computation.
The second of those bad calls to do_match_pathspec() was involved -- via either direct movement or via copying+edi...
Bash tool to get nth line from a file
...he trick, but I've been wondering if there's a Bash tool that specifically extracts a line (or a range of lines) from a file.
...
How to use the “required” attribute with a “radio” input field
...efault way of its appearance. You can follow these steps. This is just for extra info if you have any intention to modify the default behavior.
Add the following into you .css file.
/* style all elements with a required attribute */
:required {
background: red;
}
For more information you can r...
Private vs Protected - Visibility Good-Practice Concern [closed]
... sure.
There are two cases you want to extend a class:
You want to add extra functionality to a base class
You want to modify existing class that's outside the current package (in some libraries perhaps)
There's nothing wrong with private fields in the first case. The fact that people are abus...