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“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...ON DUPLICATE KEY UPDATE.
If you use INSERT IGNORE, then the row won't actually be inserted if it results in a duplicate key. But the statement won't generate an error. It generates a warning instead. These cases include:
Inserting a duplicate key in columns with PRIMARY KEY or UNIQUE constrain...
Define static method in source-file with declaration in header-file in C++
...Probably the best course of action is "do it as std lib does it". That is: All inline, all in headers.
// in the header
namespase my_namespace {
class my_standard_named_class final {
public:
static void standard_declared_defined_method () {
// even the comment is standard
...
Convert two lists into a dictionary
... elements. {k:v} or {**mapping} will construct a dict, but that's syntactically quite distinct.
– Dan Lenski
Aug 28 '19 at 16:41
...
Generator Expressions vs. List Comprehension
...or slicing
print [5,6] + gen() # generators can't be added to lists
Basically, use a generator expression if all you're doing is iterating once. If you want to store and use the generated results, then you're probably better off with a list comprehension.
Since performance is the most common rea...
Copying files using rsync from remote server to local machine
Once I've ssh'd into my remote server, what would the command be to copy all files from a directory to a local directory on my machine?
...
ASP.NET MVC on IIS 7.5
..." in Framework64 for 64-bit Windows! that bit me in the *ss. I must've installed the 32 bit verion 4 or 5 times with no effect.
– Ben Lesh
Jan 4 '11 at 15:31
14
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What is token-based authentication?
... general concept behind a
token-based authentication system is
simple. Allow users to enter their
username and password in order to
obtain a token which allows them to
fetch a specific resource - without
using their username and password.
Once their token has been obtained,
the user ...
What is the difference between isinstance('aaa', basestring) and isinstance('aaa', str)?
...trings, would it not be better to just have Unicode since that would cover all the cases? Well it is better to have only Unicode but Python was created before Unicode was the preferred method for representing strings. It takes time to transition the string type in a language with many users, in Pyth...
What is the use of interface constants?
...attern is a poor use of interfaces. That a class uses some constants internally is an implementation detail. Implementing a constant interface causes this implementation detail to leak into the class's exported API. It is of no consequence to the users of a class that the class implements a constant...
Why are functions and methods in PHP case-insensitive?
...ent little CGI programs written in C before I got sick of it, and combined all of them into a single C library. I then wrote a very simple parser that would pick tags out of HTML files and replace them with the output of the corresponding functions in the C library.
The simple parser slowly grew to ...