This article explains the database operation in python in detail
Database operation in python
1, Database programming interface
1. Connection object 2, Use built-in SQLite
1. Create database file2. Operate SQLite 3, Use of MySql database
3.1 install MySql3.2 setting environment variables3.3 start MySql3.4 using navicat for mysql management software3.5 installing PyMysql module3.6 connecti ...
Posted by fitzsic on Fri, 12 Aug 2022 21:54:17 +0300
JVM memory structure
JVM introduction
1. What is a JVM?
java virtual machine - the running environment of java programs (java Binary Bytecode operating environment)
2. Benefits of JVM
The cornerstone of writing once and running everywhere [key]Automatic memory management, garbage collection function [key]Data subscript out of range checkPolymorphism, object-ori ...
Posted by mike0193 on Fri, 12 Aug 2022 21:44:05 +0300
This article will help you understand the poll mechanism of interrupt key driver
This section continues at Take you to play interrupt mode key driver (detailed explanation) Add poll mechanismSo why do we need the poll mechanism. The previous test procedure is as follows:
while (1)
{
read(fd, &key_val, 1);
printf("key_val = 0x%x\n", key_val);
}
In the absence of the poll mechanism, most of the time the program is in the ...
Posted by DimeDropper on Fri, 12 Aug 2022 21:05:06 +0300
linux-0.11 analysis: boot file head.s Third Essay
head.s
Refer to [the blogger github][ https://github.com/sunym1993/flash-linux0.11-talk ]
Change stack top position
_pg_dir:
startup_32:
movl $0x10,%eax
mov %ax,%ds
mov %ax,%es
mov %ax,%fs
mov %ax,%gs
lss _stack_start,%esp
First, ds, es, fs, gs are all set to 0x10
And then this. lss _stack_start, esp is equivalent to pointing the top p ...
Posted by simplyi on Thu, 11 Aug 2022 21:38:03 +0300
CF1286E-Fedya the Potter Strikes Back[KMP,RMQ]
Topics
Title link: https://www.luogu.com.cn/problem/CF1286E
Topic Essentials
Define a string
s
s
The weight of s is for each
s
L
∼
...
Posted by stukov on Thu, 11 Aug 2022 21:26:50 +0300
Mysql data backup and recovery
foreword
After reading this article, delete the library and run away! ? It can never happen again! Be sure to develop the habit of risky operation of backup data to avoid wasting time in restoring data.
Contents of this article:
The role of binlog
mysqldump and mysqlbinlog do data backup and data recovery.
XtraBackup full backup and increment ...
Posted by Revan on Thu, 11 Aug 2022 21:16:22 +0300
Python magic method
Refer to the official documents of python3.7
Basic method
__class__
See__ name__
__name__
1) Current module name, of the directly running module__ name__ Is'__ main__‘， Other modules are 'module name' or 'package name. Module name'
# tmpPkg.tmp.py
print(f'tmp.py {__name__}')
# main.py
import tmpPkg ...
Posted by TubeRev on Wed, 10 Aug 2022 21:40:11 +0300
[JavaEE advanced series from beginners to engineers] detailed explanation of exception handling and solutions in JavaEE (including throws declaration exception and throw keyword)
Article catalogue
?? More relevant knowledge??
1, View exception information
??public void printStackTrace()??public String getMessage()??public String toString() 2, Exception handling - throws declares an exception
1. Why do I need throws?2. Format of throws
? Code demonstration 3. Usage scenarios of throws4. Notes on the ...
Posted by Antnee on Wed, 10 Aug 2022 21:37:40 +0300
Refactoring: reorganizing functions
1, Put a piece of code into a separate function
1.1 code example
1.2 application scenarios
When there is an overly long function or a piece of code that needs comments to make people understand its purpose, put this code into a separate function.
1.3 benefits
First, there is a greater chance that functions can be reused with each ...
Posted by TheIceman5 on Wed, 10 Aug 2022 21:29:37 +0300
Java thread pool multi thread query database to improve query efficiency
Java thread pool multi thread query database to improve query efficiency
demandproblemthinkingcodeanalysis
demand
Company data statistics report query, several large table Association query, including cross database query, data associated query, data filtering, data statistics.
problem
Main table data 1
Main table data 2
...
Statis ...
Posted by ryadex on Tue, 09 Aug 2022 22:06:04 +0300