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  Db2 Action Field

  1. Add field alter table db.table add column dddd varchar (1500) not null with default''2. Delete field alter table d

  2022-06-01 17:28:21 Views: 285
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  SQL character operation

  -- the first character of ltrim (string) clears select 'OK' + ltrim (' left and right') + 'OK'-- rtrim (stri) from consecutive spaces

  2022-06-01 17:28:06 Views: 213
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  Sqoop Chinese Handbook

  1. Overview this document mainly explains the use of SQOOP, and the reference is mainly from the official documentation of Cloudera SQOOP. In order to describe the meaning of the parameters more clearly in Chinese, almost all the instructions for the use of the parameters in this document have been verified by me.

  2022-06-01 17:28:06 Views: 216
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  Recovery process of SqlServer database corruption caused by server failure

  Fault description: 5 pieces of 2T hard disk set up RAID5, divide LUN for windows server use. The Sql Server2008 database is installed in the windows server. There are three logical partitions in the storage space, with sizes of 500G, 800G and 2, respectively.

  2022-06-01 17:28:06 Views: 257
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  Optimization of mysql database environment

  1. Environment optimization 1.1 memory optimization because the database host generally has a large memory, so it uses huge page. And try to use 80% of the memory to trade space for time. / etc/sysctl.conf configuration parameter: vm.hugetlb_shm_gro

  2022-06-01 17:28:05 Views: 209
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  Mysql DBA Advanced Operation and maintenance Learning Road-installation and configuration of heartbeat High availability Software

  1. Deployment of Heartbeat High availability requirements 1.1 operating system [root@heartbeat-1-114C] # cat / etc/redhat-release CentOS release 6.9 (Fina

  2022-06-01 17:27:50 Views: 268
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  50 suggestions for MongoDB developers Tip15

  This series of articles are translated from "50 Tips and Tricks for MongoDB Developers". I can't find the Chinese version for the time being. Anyway, I have been studying mongodb deeply recently, so I just want to translate it. On the one hand, strengthen yourself.

  2022-06-01 17:27:47 Views: 252
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  Separation of read and write by ProxySQL

  Environment: 192.168.205.37: as ProxySQL server 192.168.205.47: as Master server 192.168.205.57: as Slave serv

  2022-06-01 17:27:47 Views: 223
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  Detailed explanation of MySQL-- constraint (constraint)

  What is restraint for what? Constraints are actually the constraints of the data in the table: the purpose of adding constraints to the table is to ensure the integrity and validity of the records in the table, such as the uniqueness of some fields, and constrain some fields to the type of foreign key constraint: non-null constraint (not null) only.

  2022-06-01 17:27:47 Views: 237
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  Daily maintenance operation of mongodb index

  Create index: db.t_order_detail.createIndex ({"order_id": 1}) compound index: db.t_order_detail.createIndex ({"order_id": 1, "

  2022-06-01 17:27:46 Views: 300
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  CentOS7.3yum install zabbix3.2

  1. Environment preparation system version CentOS Linux release 7.3.1611 (Core) IP192.168.10.602, zabbix installation 2.1 install Aliyun yum configuration file rpm-ivh http

  2022-06-01 17:27:35 Views: 224
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  Operation Guide of mysql Multi-instance under CentOS

  Mysql work is everywhere, countless installation, optimization, there has been no time to organize and file, recently doing mysql Dass service, the recent problems encountered, sort out, sort out an operation guide; for your reference; preface Mysql multi-instance, that is, one server

  2022-06-01 17:27:23 Views: 254
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  MySQL deletes the database

  MySQL delete database use mysqladmin delete database use ordinary users to log in to the MySQL server, you may need specific permissions to create or delete MySQL database. So we use root users to log in, and root users have

  2022-06-01 17:27:20 Views: 248
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  Common sentences in MySQL

  Hello, Hi, everyone. What I bring to you today is "the use of commonly used sentences in MariaDB (MySQL)". 1. MySQL statements are not case-sensitive, and "parameters" are case-sensitive in Unix or Unix-like (Linux) systems. 2. Most MySQ

  2022-06-01 17:26:50 Views: 294
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  How to log in to the isqlplus page as sys in Oracle 10g

  After installing Oracle 10g on linux, we often use isqlplus to execute SQL statements. But the normal isqlplus login interface only supports login as an ordinary user, and sometimes we have to use the permissions of sys.

  2022-06-01 17:26:49 Views: 223
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  Oracle em start

  1. Set the ORACLE_SID environment variable: set ORACLE_SID=p2p takes the database with sid as P2P as an example. If it is not set, an error will be reported: UNQNAME is not set. 2. Start the service: emctl start dbconsole

  2022-06-01 17:26:49 Views: 228
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  Manage the use of SQL Server on CentOS 7

  In the previous article, we completed the functional components of SQL, so the next step is how we connect and manage to use SQL Server on this CentOS. We can download a SQL manager to connect to use, this SQL manager is recommended in https://

  2022-06-01 17:26:48 Views: 219
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  Founder of MongoDB: project managers should spend 30% of their time on programming

  Eliot Horowitz, author of this article, is the founder and technical director of MongoDB. In a technology company, software technical managers should spend no less than 30% of their total working time on programming. Whether it is managing a team, a branch, or an entire company, when

  2022-06-01 17:26:45 Views: 235
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  The solution to the large MySQL ibdata1 file

  In the MySQL database, if you do not specify the innodb_file_per_table=1 parameter to save the data of each table separately, the data of MySQL will be stored in the ibdata1 file, which will become very large over time. The following is on the reference network

  2022-06-01 17:26:44 Views: 267
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  Detailed explanation of basic use of jdbc

  JDBC, the full name of Java DataBase Connectivity / java database connection, is the most basic driver tool for using java to connect and operate the database. Sun's javasoft department developed the earliest JDBC 1.0 along with

  2022-06-01 17:26:39 Views: 294