Migration of DATA directory under Windows

1. View the current data (or insert new data) as a marker. highgo=# create table t1(id int,name text); CREATE TABL id | name ----+---------------------------------- 1 | cf9920dd1f8a7be7e56a85f8a3e018f6 2 | cf9920dd1f8a7be7e56a85f8a3e018f6 3 | cf9920dd1f8a7be7e56a85f8a3e018f6 4 | cf9920dd1f8a7be ...

Posted by conman90 on Tue, 26 May 2020 08:43:53 -0700

20. Use and principle of PageHelper paging plug-in

1. Logical paging and physical paging Logical paging: also called memory paging. Logical paging depends on the code written by the programmer. What the database returns is not the paging result, but all the data, which is then passed by the programmer The code obtains the paging data, takes out all the data, first stores it in memory, ...

Posted by ChetUbetcha on Mon, 25 May 2020 20:53:31 -0700

guava EventBus learning two source codes

Part I This paper introduces the use of event bus in guava package, and deeply understands the implementation details in the source code EventBus understand First of all, we need to look at the EventBus class. There are many comments on the class, which are summarized as follows: Eventbus ensures that subscribers will not be accessed at the sam ...

Posted by porta325 on Mon, 25 May 2020 18:25:41 -0700

MySQL installation and basic use under Linux

1. MySQL installation (install using yum) yum install mysql* –y Linux MySQL data is stored in / var/lib/mysql by default/ [root@study ~]# cd /var/lib/mysql/ [root@study mysql]# ll //Total consumption 20488 -rw-rw----. 1 mysql mysql 10485760 5 23 23:55 ibdata1 -rw-rw----. 1 mysql mysql 5242880 5 23 23:55 ib_logfile0 -rw-rw----. 1 mysql mysql 5 ...

Posted by Exemption on Sun, 24 May 2020 22:31:29 -0700

Oracle learning - database operation

Oracle tables associated with users Each user needs to determine the table storage location, which is called table space In Oracle, table space is divided into two parts: permanent table space and temporary table space Temporary table space: when using SQL statement operation, the result enters the temporary table space first Persistent table ...

Posted by tobykw13 on Sun, 24 May 2020 20:14:59 -0700

The 37th day of eggjs learning notes: the second part of RBAC on the rights management of the post management system of eggjs

1, Role addition, deletion, modification and query ① Create a new schema about role table, model > role.js Next new role.js , type the following code: module.exports = app => { const mongoose = app.mongoose; const Schema = mongoose.Schema; var d = new Date(); const RoleSchema = new Schema({ title: { type: String }, ...

Posted by nilansanjaya on Sun, 24 May 2020 08:29:34 -0700

The 37th day of eggjs learning notes: the second part of RBAC on the rights management of the post management system of eggjs

1, Role addition, deletion, modification and query ① Create a new schema about role table, model > role.js Next new role.js , type the following code: module.exports = app => { const mongoose = app.mongoose; const Schema = mongoose.Schema; var d = new Date(); const RoleSchema = new Schema({ title: { type: String }, ...

Posted by 555sandy on Sun, 24 May 2020 08:29:45 -0700

Getting started with python: crawling through pictures, articles and web pages

1, First, let's see how Python can simply crawl the web page1. Preparation The beautiful soup4 and chardet modules used in the project belong to the three-party extension package. If not, please install pip by yourself. I use pycharm to do the installation. Next, I will simply use pycharm to install chardet and beautiful soup4 Follow the steps ...

Posted by suspect on Sat, 23 May 2020 22:08:21 -0700

The last packet sent successfully to the server was 1 milliseconds ago.

Weird database exception: There are mainly two abnormal sections as follows 1. Connection reset The last packet successfully received from the server was 1 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.Na ...

Posted by TFD3 on Fri, 22 May 2020 08:03:25 -0700

Architecture design | interface idempotence principle, anti duplicate submission Token management

Source code: GitHub point here || GitEE point here 1, The concept of idempotent 1. An introduction to idempotent The characteristic of an idempotent operation in programming is that the influence of any multiple execution is the same as that of one execution. That is to say, one or more requests for a resource have the same effect. 2. HTTP req ...

Posted by careym1989 on Fri, 22 May 2020 06:59:12 -0700