[Knowledge Base]-Advanced Data Query of Database_MySQL: Reduplication, Combination Query, Connection Query, Virtual Table

Brief Book Author: seay Origin of the article: Advanced Data Query of Relational Database SQL: Reduplication, Composite Query, Connection Query, Virtual Table Recalling: [Knowledge Base]-Basic Data Query of Database_MySQL: Subquery, Group Query, Fuzzy Query   Learn [has been tested and verified] 1. Deduplication (DISTINCT) Composite queri ...

Posted on Sun, 21 Jul 2019 00:54:37 -0700 by Chris_Evans

Day61 (Routing System, Function View, Django ORM Preliminary)

1.1 Pseudo-static Pseudo-static is relative to static files, such as https://www.cnblogs.com/hesujian/p/11165818.html We call it pseudo-static, because it's not actually html static pages, it's just masquerading as html static pages. The benefits of pseudo-static: 1. Beautiful (the traditional question mark splicing looks messy) 2. Seo (Se ...

Posted on Sun, 21 Jul 2019 00:48:36 -0700 by dahwan

Operating MySql in python

Operating MySql in Python Articles Catalogue Operating MySql in Python Create database tables ** Database insertion operation** ** Database query operation** ** Database Update Operation** ** Database deletion operation** Create database tables In Python programs, execute() can be used to cr ...

Posted on Sat, 20 Jul 2019 23:27:09 -0700 by surfinglight

Problems and Solutions of redis Distributed Locks

Problems and Solutions of redis Distributed LocksDistributed LockIn distributed environment, in order to ensure normal access to business data and prevent duplicate requests, distributed locks are used to block subsequent requests. Let's start with a piece of problematic business code: Copy code public void doSomething(String userId){ User ...

Posted on Sat, 20 Jul 2019 21:37:59 -0700 by freeak08

Mongodb Performance Pressure Measurement

Background In recent days, we have done a thorough benchmark stress test on all the basic components. At present, all of our open source basic components have not been tested for performance. Often, some developers ask how much our RDS and MongoDB cluster can resist. At this time, I can't reply, because I don't know, although one of them can r ...

Posted on Sat, 20 Jul 2019 08:26:14 -0700 by phpn00bf4life

SQL Index Manager - Free GUI Tool for Index Maintenance on SQL Server and Azure

I have worked as a SQL Server DBA for more than eight years to manage and optimize server performance. In my spare time, I want to do something useful for the universe and my colleagues. This is how we ultimately provide free index maintenance tools for SQL Server and Azure. Idea Every once in a wh ...

Posted on Sat, 20 Jul 2019 07:02:36 -0700 by jshowe

Python crawler novice tutorial: mobile APP data capture pyspider

1. Mobile APP Data - Write in front Continue to practice the use of pyspider, recently searched some of the framework's usage skills, found that the document is difficult to understand, but there is no obstacle to use it for the time being, it is estimated that to write about five tutorials on the fra ...

Posted on Sat, 20 Jul 2019 05:29:18 -0700 by dwnz

Thread Safety in CoreData and SQLLite Multithread Access

Links to the original text: http://www.cnblogs.com/devinzhang/p/4699196.html Thread Safety in CoreData and SQLLite Multithread Access Database read operations are generally multi-threaded access. When reading data, we must ensure that i ...

Posted on Fri, 19 Jul 2019 20:56:47 -0700 by Jaquio

Ubuntu package dependencies broken resolution unmet dependencies

How to Solve Unmet dependencies in apt-get 21:35:22, 0930, 2017 Jinguang Liu Read 16686 Copyright Statement: This is an original article created by a blogger and may not be reproduced without the permission of the blogger.https://blog.csdn.net/u010096900/article/details/78145423 brief introducti ...

Posted on Fri, 19 Jul 2019 18:33:24 -0700 by theBond

Summary of problems encountered in server configuration of openfire

1.jdk,nginx,tomcat, database, have been installed and configured, services have been up, background login, has been reported that users do not exist, excluding network reasons (firewalls), and log writing failure (no manual creation of log directories on the new server), still not work, and later found that the database case-sensitive did not c ...

Posted on Wed, 17 Jul 2019 17:38:42 -0700 by digitallookout