大约有 23,000 项符合查询结果（耗时：0.0258秒） [XML]
Is there a REAL performance difference between INT and VARCHAR primary keys?
...ary key, then do it.
Don't use either strategy for all tables in your database. It's likely that in some cases, a natural key is better, but in other cases a surrogate key is better.
Other folks make a good point that it's rare in practice for a natural key to never change or have duplicates, s...
How To Test if Type is Primitive
...t 3: IsPrimitive = (Boolean, Byte, SByte, Int16, UInt16, Int32, UInt32, Int64, UInt64, IntPtr, UIntPtr, Char, Double, and Single),
Anther Primitive-Like type to check (t == typeof(DateTime))
share
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What optimizations can GHC be expected to perform reliably?
...ersion 7.4.2, stage 2 booted by GHC version 7.4.1
Using binary package database: /usr/lib/ghc-7.4.2/package.conf.d/package.cache
wired-in package ghc-prim mapped to ghc-prim-0.2.0.0-7d3c2c69a5e8257a04b2c679c40e2fa7
wired-in package integer-gmp mapped to integer-gmp-0.4.0.0-af3a28fdc4138858e0c7c5ecc2...
Configure WAMP server to send email
...example in the devside guide uses forwardslashes.
sendmail_path = "C:\wamp64\msmtp\msmtp.exe -d -C C:\wamp64\msmtp\msmtprc.ini -t --read-envelope-from"
mail.log = "C:\wamp64\msmtp\maillog.txt"
Create and edit the file msmtprc.ini in the same directory as your msmtp.exe file as follows, replacing...
How do I get the user agent with Flask?
...ser_agent object which contains the following attributes which are created based on the useragent string:
platform (windows, linux, macos, etc.)
browser (chrome, firefox, msie, etc.)
version
language
string (== request.headers.get('User-Agent'))
...
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
...车站的道路，抗议打车应用软件Uber。
摄影|Laurent Zabulon 图片编辑|何晞宇
强劲的扩张，伴随着出租车业、政府监管部门的阻挠和诉讼。
Uber进入纽约不到一个月，就在“纽约出租车及豪华车组织”的要求下，被迫关闭业务一个...
Convert floats to ints in Pandas?
...>> cols = ['A', 'B']
>>> df[cols] = df[cols].applymap(np.int64)
>>> print(df)
... A B C D
... 0 8 0 1.916283 6.226750
... 1 1 9 9.277504 8.522808
... 2 1 4 2.700118 7.739108
Or for a single column with apply():
>>> df['C'] = df['C']...
Error installing mysql2: Failed to build gem native extension
...\world\app\models\city.rb to look like this
class City < ActiveRecord::Base
set_table_name "city"
end
Edit the file c:\Sites\world\config\database.yml to look like this
development:
adapter: mysql2
encoding: utf8
database: world
pool: 5
username: root
password: root
socket: /tmp/mysql.sock
...
How to force HTTPS using a web.config file
... in Startup.cs
app.UseHpkp(options => options
.Sha256Pins(
"Base64 encoded SHA-256 hash of your first certificate e.g. cUPcTAZWKaASuYWhhneDttWpY3oBAkE3h2+soZS7sWs=",
"Base64 encoded SHA-256 hash of your second backup certificate e.g. M8HztCzM3elUxkcjR2S5P4hhyBNf6lHkmjAHKhpGPWE...
What is `git diff --patience` for?
...markers or signatures of important content in the text. It is still an LCS-based diff at its core, but with an important difference, as it only considers the longest common subsequence of the signature lines:
Find all lines which occur exactly once on both sides, then do longest common subsequence ...