Category：Database
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Time：2020-4-1
Preface: The previous article introduced the installation of docker tool and the use of common commands. In this article, we will introduce how to run MySQL instance in docker. Some small partners may ask: why run MySQL in docker? Because it is easy to deploy MySQL instance in docker, it does not need to consider […]
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Time：2020-4-1
brief introduction Redis is an open source (BSD licensed), memory stored data structure server, which can be used as database, cache and message queue agent. It supports string, hash table, list, set, ordered set, bitmap, hyperloglogs and other data types. Built in replication, Lua script, LRU retraction, transaction and disk persistence at different levels. At […]
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Time：2020-4-1
Check constraint A check constraint is the most common constraint type CREATE TABLE products ( product_no integer, name text, price numeric CHECK (price > 0) ); You can also give the constraint a separate name, which makes the error message clearer, or you can directly reference the constraint when you need to modify it CREATE […]
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Time：2020-4-1
Scene description Hybrid HTAP database requirements: for example, Oracle database transformation on cloud, cloud database scheme selection; OLTP system query is slow, there are analytical scenarios and bottleneck customers!. Solve the problem Real time complex query: improve the performance of analysis query and reduce the synchronization delay of online business data Aggregate polardb and ADB […]
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Time：2020-4-1
Release Notes 1. If the accesstoken is not set, illegal request to maliciously construct configuration key traversable read file vulnerability repair; (from: 360 code guard team) 2. Project name regular verification problem repair, project name in the dash separation, configuration point separation; 3. Bottom HTTP tool class optimization; 4. Restful interface format adjustment, changed to […]
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Time：2020-4-1
According to personal coding habits, for reference only If you see something in a circle halfway, you can go to the official website to check it Import module var mongoose = require(“mongoose”); Connect to database mongoose.connect(“mongodb://localhost/mongoose_test”); Link state mongoose.connection.once(“open”,function () { Console.log (“database link succeeded”); }); Make a callback to see if the link is […]
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Time：2020-3-31
Mac login MySQL error 1045 (28000): access denied for user ‘root’ @ ‘localhost’ (using password: no) Environmental Science MySQL version: 5.7.12Operating system: OSX 10.14.6 (18g84)Installation file:. DMG download installation package (I selectedMacOS 10.14 (x86, 64 bit), DMG ArchiveVersion download of) Mysql-5.7.26-mac OS 10.14-x86_.dmg Step 1 Close the MySQL service. Whether you open MySQL service or […]
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Time：2020-3-31
Preface Because it is installed on a personal virtual machine and can be connected to the public network, and what is actually used through VMware is your CD-ROM image, so the local Yum source can be installed directly using Yum without configuration. Operating system installation 1、 Download and install VMware, prepare centos7 image ISOThere is […]
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Time：2020-3-31
Based on the custom form system of Vue and nodejs, the project address is transmitted to https://github.com/kkxiaojun/vueform brief introduction This system decided to use Vue as the overall framework of the web, nodejs as the server language, mongodb as the preferred data storage scheme. This system includes the current situation of custom form system, system […]
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Time：2020-3-31
Redis provides two persistence methods, one is RDB based on snapshot form, the other is AOF based on log form, each of which has its own advantages and disadvantages. This article will introduce the two persistence methods of redis, hoping that you will have a more comprehensive and clear understanding of these two methods after […]
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Time：2020-3-31
brief introduction In PostgreSQL 12, the JSON function document is updated, and three new methods with jsonpath query statement parameters are added: jsonb_path_exists(target jsonb, path jsonpath [, vars jsonb [, silent bool]]) jsonb_path_match(target jsonb, path jsonpath [, vars jsonb [, silent bool]]) jsonb_path_query(target jsonb, path jsonpath [, vars jsonb [, silent bool]]) It can solve […]
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Time：2020-3-31
Syntax based optimization and simple query conditions. Syntax based optimization refers to the selection of words and the order of writing in SQL statements without considering any non grammatical factors (such as index, table size and storage). general rule In this section, I’ll look at some general rules that you need to pay attention to […]
