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Foreign key constraints: When to use ON UPDATE and ON DELETE
... "I wouldn't want a customer delete to wipe out the financial data for the orders he had previously." In a situation like that, you probably still need the customer's data anyway. Your design should probably be marking the customer as inactive, not deleting their row from the database. In practice...
What's the idiomatic syntax for prepending to a short python list?
... element will be prepended one at a time, thus effectively reversing their order.
Performance of list versus deque
First we setup with some iterative prepending:
import timeit
from collections import deque
def list_insert_0():
l = []
for i in range(20):
l.insert(0, i)
def list_s...
How to write a large buffer into a binary file in C++, fast?
...
Try the following, in order:
Smaller buffer size. Writing ~2 MiB at a time might be a good start. On my last laptop, ~512 KiB was the sweet spot, but I haven't tested on my SSD yet.
Note: I've noticed that very large buffers tend to decrease pe...
Can I multiply strings in Java to repeat sequences? [duplicate]
...
You have to make some assumptions in order to solve real world problems. In this case, I'm using maven on my current project. I have a pom.xml set up with the commons-lang dependency. It made it easier for me to answer his question, in short. And I'm not exactly...
Returning an array using C
... from Java programming, I am used to being able to say int [] method() in order to return an array. However, I have found out that with C you have to use pointers for arrays when you return them. Being a new programmer, I really do not understand this at all, even with the many forums I have looked...
Proper way to declare custom exceptions in modern Python?
...eption(Exception):
pass
Again, the problem with the above is that in order to catch it, you'll either have to name it specifically (importing it if created elsewhere) or catch Exception, (but you're probably not prepared to handle all types of Exceptions, and you should only catch exceptions y...
How to find Unused Amazon EC2 Security groups
... Display Security Groups left to audit / delete
echo "select * from groups order by groupid" | mysql $DBCONFIG $DB | sed 's/groupid\t/groupid\t\t/'
And here is the sql to create the database.
-- MySQL dump 10.13 Distrib 5.5.41, for debian-linux-gnu (x86_64)
--
-- Host: localhost Database: aws...
Best practices for exception management in Java or C# [closed]
...ion handling should be something around these guidelines, in no particular order:
For the sake of maintainability, always log exceptions so that when you start seeing bugs, the log will assist in pointing you to the place your bug has likely started. Never leave printStackTrace() or the likes of i...
Shell one liner to prepend to a file
...bash example above that the double quotes span over the carriage return in order to demonstrate prepending multiple lines. Check your shell and text editor are being cooperative. \r\n comes to mind.
– John Mee
Mar 19 '10 at 5:05
...
Is there more to an interface than having the correct methods
... should provide inheritance, encapsulation, modularity and polymorphism in order to be a fully-featured Object Oriented language. In dynamically-typed - or duck typed - languages (like Smalltalk,) polymorphism is trivial; however, in statically typed languages (like Java or C#,) polymorphism is far...