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When and why are database joins expensive?
... Database Writings 1988-1991 but this book was later rolled into edition six of Introduction to Database Systems, which is the definitive text on database theory and design, in its eighth edition as I write and likely to remain in print for decades to come. Chris Date was an expert in this field whe...
Simple way to encode a string according to a password?
...mport base64
def encode(key, string):
encoded_chars = []
for i in xrange(len(string)):
key_c = key[i % len(key)]
encoded_c = chr(ord(string[i]) + ord(key_c) % 256)
encoded_chars.append(encoded_c)
encoded_string = "".join(encoded_chars)
return base64.urlsafe_b...
Generating v5 UUID. What is name and namespace?
...bability. The Wikipedia entry for the Birthday Problem (aka Birthday Paradox) includes a table that gives the probabilities of at least one collision for various numbers of keys and table sizes. For 128-bits, hashing 26 billion keys this way has a probability of collision of p=10^-18 (negligible), b...
Prototypical inheritance - writing up [duplicate]
So I have these 2 examples, from javascript.info:
2 Answers
2
...
Creating range in JavaScript - strange syntax
...r); //['0', '1', '2']
arr.length; //3, implies arr[3] === undefined
//we expand the array by 1 item
arr.length = 4;
arr[3]; //undefined
arr.hasOwnProperty(3); //false
Object.keys(arr); //['0', '1', '2']
We get to the inherent difference between the number of items in the array, arr.length, and th...
Google Maps Android API v2 - Interactive InfoWindow (like in original android google maps)
...o I had to roll my own which I would like to share here with you. (Please excuse my bad English) (It's a little crazy to answer another Czech guy in English :-) )
The first thing I tried was to use a good old PopupWindow. It's quite easy - one only has to listen to the OnMarkerClickListener and the...
Python str vs unicode types
...
unicode is meant to handle text. Text is a sequence of code points which may be bigger than a single byte. Text can be encoded in a specific encoding to represent the text as raw bytes(e.g. utf-8, latin-1...).
Note that unicode is not encoded! The inter...
Uber5岁了，一次性告诉你它的商业之道 - 资讯 - 清泛网 - 专注C/C++及内核技术
...务。其中专车服务按照车型和费用由低至高主要分为UberX(普通轿车)，UberXL(加长轿车)，UberBlack(豪华车)；最受质疑的则是以私家车为主要承租群体的“拼车”服务。在美国，这项服务称为“UberPool”，在欧洲为“UberPop”,在中国，...
What is the best Distributed Brute Force countermeasure?
... would work in combination with other best-practices approaches to auth: fixed-username throttling, per-IP throttling, code-enforced strong password policy, unthrottled cookie login, hashing all password equivalents before saving them, never using security questions, etc.
Assumptions about the att...
Git-Based Source Control in the Enterprise: Suggested Tools and Practices?
I use git for personal projects and think it's great. It's fast, flexible, powerful, and works great for remote development.
...