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Multiple columns index when using the declarative ORM extension of sqlalchemy
...e just Column objects, index=True flag works normally:
class A(Base):
__tablename__ = 'table_A'
id = Column(Integer, primary_key=True)
a = Column(String(32), index=True)
b = Column(String(32), index=True)
if you'd like a composite index, again Table is present here as usual you ju...
Assignment inside lambda expression in Python
...asons. For example, we will be able to write the following:
import sys
say_hello = lambda: (
message := "Hello world",
sys.stdout.write(message + "\n")
)[-1]
say_hello()
In Python 2, it was possible to perform local assignments as a side effect of list comprehensions.
import sys
say_hell...
MySQL DROP all tables, ignoring foreign keys
... your database like this:
SELECT concat('DROP TABLE IF EXISTS `', table_name, '`;')
FROM information_schema.tables
WHERE table_schema = 'MyDatabaseName';
Note 1: This does not execute the DROP statements, it just gives you a list of them. You will need to cut and paste the output into your SQL...
Saving an Object (Data persistence)
...tion of it to your example:
import pickle
class Company(object):
def __init__(self, name, value):
self.name = name
self.value = value
with open('company_data.pkl', 'wb') as output:
company1 = Company('banana', 40)
pickle.dump(company1, output, pickle.HIGHEST_PROTOCOL)
...
What is the instanceof operator in JavaScript?
...there.
Every object in JavaScript has a prototype, accessible through the __proto__ property. Functions also have a prototype property, which is the initial __proto__ for any objects created by them. When a function is created, it is given a unique object for prototype. The instanceof operator uses...
How to open link in new tab on html?
...
Set the 'target' attribute of the link to _blank:
<a href="#" target="_blank" rel="noopener noreferrer">Link</a>
Edit: for other examples, see here: http://www.w3schools.com/tags/att_a_target.asp
(Note: I previously suggested blank instead of _blank beca...
Multiple glibc libraries on a single host
...r search for libraries in /path/to/newglibc (so you wouldn't have to set LD_LIBRARY_PATH before running it), and the -dynamic-linker option will "bake" path to correct ld-linux.so.2 into the application.
If you can't relink the myapp application (e.g. because it is a third-party binary), not all is...
GET URL parameter in PHP
...
$_GET is not a function or language construct—it's just a variable (an array). Try:
<?php
echo $_GET['link'];
In particular, it's a superglobal: a built-in variable that's populated by PHP and is available in all scope...
OceanBase使用libeasy原理源码分析：服务器端 - 数据库(内核) - 清泛网 - ...
...、OceanBase启动时的使用模式
二、 基础数据结构
2.1 easy_list_t
2.2 easy_pool_t
2.3 easy_buf_t
2.4 easy_connection_t
三、 连接建立
四、 同步处理(OceanBase少量使用这种模式)
五、 异步处理(OceanBase大量采用这种模式)
六、 资源管理
...
C/C++获取Windows的CPU、内存、硬盘使用率 - C/C++ - 清泛网 - 专注C/C++及内核技术
...率1.获取Windows系统内存使用率 Win 内存 使用率 DWORD getWin_MemUsage(){MEMORYSTATUS ms;::GlobalMemoryStatus(&ms);return ms.d...1.获取Windows系统内存使用率
//Win 内存 使用率
DWORD getWin_MemUsage()
{
MEMORYSTATUS ms;
::GlobalMemoryStatus(&ms);
return ms.dwMe...