• “Learning Flink from 0 to 1” — introducing stream windows in Flink


    preface At present, there are many scenarios of data analysis that evolve from batch processing to stream processing. Although batch processing can be treated as a special case of stream processing, analyzing an infinite set of stream data usually requires a change in thinking mode and has its own terms (for example, “windowing”, “at least […]

  • Installing Linux QQ for Ubuntu


    environment-System: Linux / Ubuntu 20.04lts-QQ:Linux QQ V2.0.0 technological process1. Download the installation packagehttps://im.qq.com/linuxqq/dow…, because it is Ubuntu, download the installation package in. DEB format, and select the format according to the Linux distribution you use! 2. How to install? -The current version of Linux QQ depends on gtk2.0. Please ensure that your system has gtk2.0 […]

  • The concept of trigger and its syntax / create trigger / view and delete


    Triggers can simply understand a special stored procedure. The variable definitions and process statements of previous stored procedures are also suitable for triggers. The only difference is that we only need to define triggers instead of calling triggers manually. From the perspective of event triggering, the process of writing a trigger is the process of […]

  • 12800 words! Quick manual of SQL syntax (full of dry goods, recommended collection!)


    Author: Silent VoidOriginal text:https://juejin.im/post/5c7e52… This paper aims at the general syntax of relational database. Limited by space, this paper focuses on the usage and will not explain the characteristics and principles. 1、 Basic concepts Database terminology Database – A container (usually a file or group of files) that holds organized data. Data table – A structured list […]

  • How do I configure springboot quartz?


    package org.fh.util;import java.util.Map;import org.quartz.CronScheduleBuilder;import org.quartz.CronTrigger;import org.quartz.Job;import org.quartz.JobBuilder;import org.quartz.JobDetail;import org.quartz.JobKey;import org.quartz.Scheduler; import org.quartz.SchedulerFactory;import org.quartz.TriggerBuilder;import org.quartz.TriggerKey;import org.quartz.impl.StdSchedulerFactory; /** Description: scheduled task management class Author: FH admin from: fhadmin.org */ public class QuartzManager { private static SchedulerFactory gSchedulerFactory = new StdSchedulerFactory(); // Create a schedulerfactory factory instance private static String JOB_ GROUP_ NAME = “FH_ JOBGROUP_ NAME”; // […]

  • An article deals with MySQL commands


    The basic operations of MySQL can include two aspects: common MySQL statements, such as the frequently used add, delete, modify and query (crud) statements, and advanced MySQL functions, such as stored procedures, triggers, transaction processing, etc. These two aspects can be subdivided as follows: MySQL common statements Crud of table (or database) Crud of table […]

  • Ubuntu installation: sogoupinyin package fcitx-frontend-qt4 dependency is not installed


    environment Linux/Ubuntu20.04LTS sogoupinyin_2.3.1.0112_amd64.deb sogoupinyin_2.4.0.3469_amd64.deb fcitx-frontend-qt4 download https://pinyin.sogou.com/linux/ abnormal Install sogoupinyin_ The software package fcitx-frontend-qt4 is not installed when amd64.deb Selecting unselected package sogoupinyin. (Reading database… The system currently has 186515 files and directories installed.) Prepare to unzip sogoupinyin_ amd64.deb … Decompressing sogoupinyin ( Dpkg: the dependency problem makes the configuration of sogoupinyin unable […]

  • Task scheduling web management platform based on ASP. Net core 5.0 and relying on quartz. Net framework


    Source address:  https://github.com/246850/Calamus.TaskScheduler Demo address:     1. Quartz.net framework core classes Ischeduler: dispatcher Ijobdetail: task Itrigger: trigger Jobkey: task / trigger ID Jobdatamap: packet 2. Email notification (fluent email Class Library) _fluentEmail.To(to).Subject(subject).Body(body, true).SendAsync(); 3. Quartz.net is hosted by ihostedservice background service internal class QuartzHostedService : IHostedService { private readonly ISchedulerFactory schedulerFactory; private readonly IOptions […]

  • Springboot quartz scheduled task tool class


    package org.fh.util; quartz springboot This work adoptsCC agreement, reprint must indicate the author and the link to this article

  • MSYQL trigger


    preface When our database becomes absolutely complex, association deletion becomes impractical. At this time, we think of using soft deletion instead of deletion, but soft deletion does not delete the data, and the data still exists. When we have a unique field in the table, such as the username field in the user table, we […]

  • FPGA / IC position — Summary of common questions in written interview of large companies


    FPGA / IC position — Summary of common questions in written interview of large companies1: What are synchronous logic and asynchronous logic?Synchronization logic is that there is a fixed causal relationship between clocks. Asynchronous logic is that there is no fixed causal relationship between clocks. The answer should be consistent with the above question (Supplement): […]

  • Edition-Based Redefinition


    Oracle introduced edition based redefinition (EBR) in 11g to solve the problem of updating database objects, such as PL / SQL programs and views. If the object is locked, the update must wait. If the update is to be completed immediately, the application needs to be stopped. The implementation method is to create a version, […]