Django Foundation - Notes - Model Class

Model Model configuration Addition and deletion of data Add: book = BookInfo() book.save() and BookInfo.objects.create() Delete: book.delete() and BookInfo.objects.get().delete() Change: book.name ='xxx'book.save() and BookInfo. objects. get (). update (name = xxxx) Query of data Basic query F object an ...

Posted on Mon, 23 Sep 2019 03:56:39 -0700 by gabeg

mysql Json Column uses

mysql json column ## Use scenarios When we create tables, we are always used to reserve more columns in order to prevent future demand increases or changes. If we add columns of tables, we lock tables in a very large amount of data. But if we add associated tables, queries will slow down. Most of the ...

Posted on Mon, 23 Sep 2019 02:52:28 -0700 by azaidi7

Data source configuration in Spring Boot (Spring Boot dbcp2 data source configuration)

Database Connection Pool Selection Algorithms By default, database connections can be automatically configured using the DataSource pool. The following is an algorithm for selecting a specific implementation: Because of the performance and concurrency of Tomcat's data source connection pool, we always give preference to Tomcat when it is avail ...

Posted on Sat, 21 Sep 2019 03:08:51 -0700 by bashaash

mybatis basic xml configuration

If the article is wrong, please comment downstairs, thank you for your positive correction! Learn together and become a big man! mybatis: 1. lightweight 2. Advanced mapping (mapping between entity classes and database table fields) allows you to manipulate entity classes in subsequent development without paying attention to the database. (In fa ...

Posted on Sat, 21 Sep 2019 00:41:32 -0700 by pramodv

Analysis of gh-ost Principle

gh-ost principle Introduction The last article introduced gh-ost parameters and specific methods of use, as well as the core features - dynamic adjustable pause, dynamic modification parameters and so on. This paper explains gh-ost's execution process, data migration and handover details design from the source code. Two principle 2.1 Implementa ...

Posted on Fri, 20 Sep 2019 02:08:10 -0700 by hehachris

How does Spring Boot integrate multiple data sources?

SpringBoot is now a backend framework for many companies because it builds faster and integrates other third parties better and faster. So, with the increase of business volume, it will be related to sub-library and sub-table. Although this word sounds familiar and easy to understand as a programmer, I think many readers have not touched too m ...

Posted on Fri, 20 Sep 2019 01:18:30 -0700 by B-truE

MySQL database - CRUD for tables

CRUD: Create, Retrieve, Update, Delete 1. Create The syntax for creating a table has been explained in the previous blog, so here we will create a student table directly mysql> create table student( -> id int unsigned primary key auto_increment, -> name varchar(32) not null, - ...

Posted on Thu, 19 Sep 2019 19:18:09 -0700 by coder9

MySQL database related operations in python

Installation Basic Environment 1 Introduction MySQL is developed on the basis of TCP protocol, but after network connection, the data transmitted must follow the protocol of MySQL, encapsulating the package of MySQL protocol, which is the driver. MySQL Driver MySQLDB's most famous library, which encapsulates and implements MySQL's C Clien ...

Posted on Thu, 19 Sep 2019 07:12:15 -0700 by BITRU

Don't come and see? I'll teach you how to speculate in stocks.

Recently, stock speculation is to buy what falls, has been losing money, cry, as a person who has learned python how to tolerate, before also speculated in the stock that use the k-line like Yang Baoyin to select the stock is good. So just do it. I can use python to write a stock selection program. Good! idea is the first step, how to achieve i ...

Posted on Thu, 19 Sep 2019 07:02:46 -0700 by Fjerpje

Spring Boot + Jpa + Thymeleaf Comprehensive Practice

In the previous course, we learned Spring Boot Web development, JPA database operation, Thymeleaf and page interaction technology. This course integrates these contents to make a user management function, including displaying user list (paging), adding users, modifying users and deleting users. Some people say that programmers are adding, dele ...

Posted on Thu, 19 Sep 2019 06:51:22 -0700 by Panz3r