Programming VIP

1, Understand what preprocessing is Data preprocessing is a data mining technology. Its essence is to convert the original data into an understandable format or in line with our mining format. 2, Why preprocessing In the real world, data is usually incomplete (lack of some interesting attribute values), inconsistent (including difference ...

1. Introduction to Orch Orchestrator (orch): MySQL high availability and replication topology management tool written by go, which supports the adjustment of replication topology, automatic failover and manual master-slave switching. The back-end database uses MySQL or SQLite to store metadata, and provides a Web interface to display the topol ...

1, JSON and JSONB Compared with other relational databases, Postgresql has a great advantage in that it has built-in many special data types, such as inet and MAC. The json and json types introduced in this paper are also two unique data types of Postgresql. In fact, their essence is to store data in jon format, However, the difference is that ...

First of all, I want to briefly explain that this article is translated from mysql manual , and through my integration, there are many text contents, but the actual gold content is relatively high, I suggest you read it carefully, There must be harvest. 1. GROUP BY optimization The most common way to satisfy a GROUP BY clause is to scan t ...

catalogue Addition and subtraction of tables What is set operation Addition of tables -- UNION Precautions for set operation Set operation with duplicate rows - ALL option Select the common part in the table - INTERSECT (intersection) Recorded subtraction - Excel (difference set) Join (join tables in columns) What is connection IN ...

Five data types key creation View all key s in the current library keys * Determine whether a key exists exists key View the type of key type key Delete key del key unlink key --Asynchronous deletion Set the expiration time of the key expire key 10 See how many seconds are left to expire ttl key ---1 Means never ...

The original content of GreatSQL community cannot be used without authorization. Please contact Xiaobian and indicate the source for reprint.brief introductionPrometheus is an open-source combination of monitoring & Alarm & time series database. Usually, Kubernetes will cooperate with Prometheus for monitoring. Because the image of Prom ...

Usage Summary of diasql preface: Last time, the DM8 database was built in linux, but it was not initialized. sql statements were tested and disql was used. This blog records the initialization under linux and summarizes how to use disql. For the installation of DM8, please refer to my previous blog: Link: Installation of DM8 (win and lin ...

*1 * ***** 0 * * * introduction Why index? In general application systems, the read-write ratio is about 10:1, and there are few performance problems in insert operations and general update operations. In the production environment, we encounter the most and most prone to problems, or some complex query operations. Therefore, the optimization ...

java Transformation Road - database (I) Those who discipline themselves are enough to convince others, and small steps can reach thousands of miles. As mobile developers, although they are familiar with java syntax, they are only the tip of the iceberg for back-end development. Self discipline is not a temporary brain fever. Ideas need to be ...