Basic usage of django2.0 models.py

ORM model Before writing the basic usage of models.py, let's first understand the disadvantages of our own writing of sql: As we write more and more projects, if we continue to use native sql statements to write, the following problems will occur: The reuse rate of SQL statements is not high. The mor ...

Posted on Sat, 01 Feb 2020 02:29:42 -0500 by ankur0101

Java database 03 connection pool

1 connection pool 1.1 INTRODUCTION In actual development, "get Connection" or "release resources" are two processes that consume system resources very much. In order to solve this kind of performance problem, we usually use Connection pool technology to share Connection. In this way, we don't need to creat ...

Posted on Fri, 31 Jan 2020 17:07:16 -0500 by jaronblake

mysql advanced (1) lecture 1-13

1.mysql configuration file I. linux:/etc/my.cnf file windows:my.ini file Binary log logbin: master-slave copy error log: it is off by default, recording serious warning and error information, details of each startup and shutdown. Query log: log Data file:. myd (store data). myi (store index) frm (store table structure) 2, ...

Posted on Fri, 31 Jan 2020 16:28:53 -0500 by Cheers

Performance comparison of mysql batch operation

1, When operating the database, using the prepared statement will greatly improve the performance advantages of operating the database as follows: 1). Readability and maintainability of the code. (use placeholders to represent parameters?) 2) can maximize performance (precompile), MySQL does not support performance optimizat ...

Posted on Fri, 31 Jan 2020 14:07:15 -0500 by leebo

Java implementation file click does not respond

Java implementation file click does not respond jsp page link, click visit action to download the file on the server with IO stream, the problem is that no response is given to any click, and no error is reported in the log. Foreground ajax code Ext.Ajax.request({ url : '/yjy/training/TrainingTimeAction.do?method=downLoadAttchById', params : { ...

Posted on Fri, 31 Jan 2020 05:02:16 -0500 by Jamiek

SSIS circulates the output of CSV file by month according to the month and month in the Query Library and names it dynamically in that month

SSIS circulates the CSV file by month according to the month and year in the Query Library and names it by that month. Let's take a look at the overall structure. Control flow: Data flow: First of all, we do a task to execute sql. The configuration is as follows: Result set configuration: Note that the variables in the ...

Posted on Fri, 31 Jan 2020 04:33:55 -0500 by overlordofevil

Python uses database (SQLite)

SQLite is an embedded database whose database is a file. Because SQLite itself is written in C and its volume is very small, it is often integrated into various applications, even in iOS and Android apps. SQLite3 is built in Python, so you don't need to install anything to use SQLite in Python. Before using SQLite, we need to understand several ...

Posted on Fri, 31 Jan 2020 04:31:09 -0500 by littlejay

What is the syntax of inner join in LINQ to SQL?

I'm writing a LINQ to SQL statement, and I'm using the standard syntax of a regular inner join with an ON clause in C. How do you represent the following in LINQ to SQL: select DealerContact.* from Dealer inner join DealerContact on Dealer.DealerID = DealerContact.DealerID #1 building In fact, it's usually best not to join linq. Wh ...

Posted on Thu, 30 Jan 2020 10:29:40 -0500 by shedokan

Learn design pattern (creation) from Spring and Mybatis framework source code

Design pattern is the solution to the problem. Learning the use of design pattern from the code of God can effectively improve the ability of personal coding and design code. This series of blog is used to summarize the design patterns used in the read framework source code (Spring series, Mybatis) and ...

Posted on Thu, 30 Jan 2020 09:56:16 -0500 by JonathanS

Learn koa2(8) from zero -- connect MySQL and simple operation

This one doesn't write demo, because the next one makes a simple memo practice, which can be used as an example. install Just go to the official website to download mysql. Then the MySQL module of node is introduced. npm install --save mysql Use Create database session const mysql = require('mysql') const c ...

Posted on Wed, 29 Jan 2020 11:10:15 -0500 by Blob