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  Query of commonly used Mongodb commands

  After the last article talked about the addition, deletion and modification of mongodb, this article will explain its powerful query function. First, the introduction and preliminary study of the find command the query in mongodb uses the find () command. He has two parameters, the first of which is your query condition (the default is {}.

  2022-06-01 10:47:01 Views: 258
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  Redis configuration explanation

  The installation of redis has been introduced earlier, and then the configuration parameters of redis are briefly introduced. 1.Redis generic configuration daemonize no # by default, redis does not run as daemon. Through daemon

  2022-06-01 10:47:01 Views: 286
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  A detailed case study of PHP Operation Redis

  $redis = new Redis (); connect, open link redis service parameter host: string, service address port: int, port number timeout: float, link duration (optional

  2022-06-01 10:47:00 Views: 281
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  How does SQL-server establish a connection with visual studio

  How SQL-server establishes a connection with visual studio to open the database. Right-click to create a new database wl. Create a new table: you can create it manually or using commands. Click the wins icon on your computer and type SQL-se on the command line

  2022-06-01 10:46:53 Views: 216
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  CentOS system installs JDK

  Download jdk from oracle needless to say tar zxvf * .tar.gz (* .tar.gz is the name of the downloaded file, decompress.) Mv * jdk (* is the folder you unzipped. Change your name and I will change it.

  2022-06-01 10:46:52 Views: 213
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  Linux installs mysql8.0.12 using the glibc version

  1. Preface: although it is very convenient to install yum, there is no way to use yum source if you do not have a public network. So we can install it using the glibc version of the installation package provided by mysql. But before installing, be sure to delete the previous version, package

  2022-06-01 10:46:37 Views: 240
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  Mongodb index

  The principle of indexing is that when multiple documents are inserted into each collection, each document will have a location information after being persisted by the underlying storage engine. Through this location information, the document MMAPv1: file id+ file offsetWiredTige can be read from the storage engine.

  2022-06-01 10:46:34 Views: 220
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  Rapid installation and deployment of Lepus Database Monitoring system

  Lepus database monitoring system installation practice Part1: written in the front Lepus installation requires Lamp environment, Lamp environment installation personal think is more difficult, one-click deployment of XAMPP LAMP environment is easy and labor-saving, lepus official website manual also recommends using

  2022-06-01 10:46:19 Views: 206
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  Backup validity check script based on XtraBackup

  The MySQL of the production environment schedules hot backup scripts to back up data regularly through crontab. At present, hot standby is realized through XtraBackup software. For hot standby scripts, please check out my previous blog, "using shell to achieve mysql automatic complete, add &"

  2022-06-01 10:46:18 Views: 267
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  Detailed explanation of sysctl and / proc

  Directory 1, introduction to sysctl 2, use of sysctl commands 3, sysctl configuration file / etc/sysctl.conf detailed explanation 4, introduction to / proc directory 5, kernel file and variables in configuration file sysctl.conf under / proc/sys

  2022-06-01 10:46:18 Views: 278
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  What is the keyword of the unique index in mysql

  This article shows you what is the only index keyword in mysql, the code is concise and easy to understand, it can definitely brighten your eyes. I hope you can get something through the detailed introduction of this article. The keyword for the only index in mysql is unique index. Chuang

  2022-06-01 10:46:15 Views: 270
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  MySQL master-slave replication project (MHA+ dual master Keepalived) _ MySQL highly available replication and distributed cluster architecture 04

  MySQL Master-Slave replication Project (MHA+ dual Master Keepalived) _ MySQL High availability replication and distributed Cluster Architecture 04 Video tutorial Learning address http://edu.51cto.com/course/14280.htmlOrac

  2022-06-01 10:46:13 Views: 244
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  Migrate tables and indexes from the user's current tablespace to another tablespace

  View the storage of INV users' objects select * from dba_segments ds where ds.owner='INV';--default tablespace users create tablespace INV

  2022-06-01 10:46:13 Views: 246
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  Summarize the basic operations of MongoDB database

  This article mainly explains the basic operation of summarizing MongoDB database, the content is clear and clear, interested friends can learn, I believe it will be helpful after reading. This paper describes the basic operation of MongoDB database with an example. Share it with you for your reference, such as

  2022-06-01 10:46:10 Views: 236
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  What else can you do if DBA doesn't copy and paste? Think about it.

  In fact, it is a very LOW thing to check the documents at the customer site and type according to the orders. the problem is that very often, your laptop and mobile phone are not allowed at the scene, what do you do? Many commonly used commands we need to remember, casually squeeze, spend half an hour every day while typing to understand is a good way to learn. Below.

  2022-06-01 10:46:10 Views: 210
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  UDE-12154: operation generated ORACLE error 12154

  [oracle@PLUSTEST ~] $expdp system/gacHZdba2018@PLUSDEV directory=dump_dir dumpfile=plusdevschema.dmp

  2022-06-01 10:46:09 Views: 215
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  Scn explanation in Oracle

  SCNSystem Change Numbers (SCNs) & System Commit Numbers (system change number & system submission number) A system change number (SCN) is a

  2022-06-01 10:46:09 Views: 237
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  Oracle some commands

  On windows server2008r2, oracle11g starts the EM command: 1. In the start run, type set ORACLE_SID=orcl (the instance name of your library) 2. Run emctl start dbcons

  2022-06-01 10:46:09 Views: 290
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  SqlServer series notes-- creation and maintenance of tables

  -- create table create table Employees (EmployeeID Int primary key, Name VarChar (10) NOT NULL,Sex Char (2) defaul

  2022-06-01 10:46:08 Views: 212
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  08 redis data type: hash

  # introduction to hash in memcached, we often package some structured information into hashmap, which is serialized and stored as a string value on the client (usually in json format), such as the user's nickname, age, gender, points, etc. # Common life

  2022-06-01 10:46:05 Views: 238