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  How to use Next-Key Lock in Mysql

  This paper takes Next-Key Lock as an example to analyze the use of Next-Key Lock in Mysql. After reading the complete article, I believe you have a certain understanding of the use of Next-Key Lock in Mysql. Connection and thread view connection

  2022-06-01 17:54:20 Views: 226
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  Query the size of all tables in oracle data

  Select t.bytesgraded toddler Char ((t.bytes) / (1024,1024), '999G999D999'), t.* from sys.dba_segments t where t.owne

  2022-06-01 17:54:20 Views: 249
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  Media Recovery error in Oracle non-archiving mode-- ORA-26040

  Oracle non-archived mode Media Recovery error-- ORA-26040 system environment: operating system: Linux RH55Oracle: Oracle 11gR2 simulation case: 1. View database mode 18:12:3

  2022-06-01 17:54:19 Views: 254
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  [Oracle Database] Oracle RAC (IX): SCAN

  The role of SCAN is to simplify the configuration of the client to connect to the database. The SCAN name of the node will remain the same regardless of whether the cluster is added or deleted, and the client does not need to make any changes. SCAN is a name that is resolved through DNS to up to 3 IP addresses (SCAN VIP) SC

  2022-06-01 17:54:19 Views: 229
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  Introduction to the method of calculating percentage by MySQL

  According to the corresponding conditions, extract the corresponding count number (myCount), extract the total number of count (totalCount) to calculate the percentage: myCount / totalCount * 100rounding: use the ROUND function ROUND (nu)

  2022-06-01 17:54:19 Views: 257
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  Methods of collecting and viewing statistical information in Oracle

  The statistics in the Oracle database are a set of data that are stored in the data dictionary and describe the details of the objects in the Oracle database from multiple dimensions. CBO uses these statistics to calculate the cost of various possible and different execution paths of the target SQL, and from

  2022-06-01 17:53:19 Views: 201
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  MongoDB errmsg access denied use admin db ok 0

  When using MongoDB, sometimes the message "{" errmsg ":" access denied use admin db "," ok ": 0"} appears when executing certain commands, because these commands require use admin db

  2022-06-01 17:53:16 Views: 278
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  Considerations for the initial installation of oracle12C under windows

  Oracle12C Note (1). Windows to run the setup.exe check as an administrator still prompts: make sure the current user has the permissions to access the temporary location. Answer: set the drive letter where the installation directory is located to share (the share name is drive letter + $). (2)

  2022-06-01 17:53:15 Views: 241
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  MYSQL (3) optimal selection of data types

  Integer type: Tinyint-8Smallint-16Mediumint-24Int-32Bigint-64 real type (number with decimal part) Float-4/double-8: floating point Decimal: exact (just save

  2022-06-01 17:53:01 Views: 205
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  MongoDB (4): aggregation framework

  1. Introduce the aggregation framework of MongoDB, which is mainly used to transform and combine the documents in the collection, so as to analyze the data and make use of it. The basic idea of the aggregation framework is to use multiple components to create a pipeline for processing a series of documents. These components include: filtering (

  2022-06-01 17:53:01 Views: 251
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  Summary of T-SQL statements

  Today, I would like to share with you about the SQL sentence, the usage and syntax of T-SQL, as well as some examples. The purpose is to help you review the basic sentences of T-SQL so that they can be used more quickly in the project. Of course, it is more important for beginners to learn and summarize. I personally feel

  2022-06-01 17:53:00 Views: 274
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  Mongodb addition, deletion, modification and search

  (1) add: db.collname.insert ({name: "user1", age: "20"}) add a regular data. The added number is a key-value pair in json format, followed by double quotation marks or quotation marks db.collnam.

  2022-06-01 17:53:00 Views: 232
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  Export data to a csv file using the sqlplus tool, requiring the file to be time-stamped

  Now that the business department has a demand, it is necessary to export some specific data in the database at a fixed time every day, and it is best to distinguish and archive according to the date name. Oracle's sqlplus tool is chosen here. The reason is that it is simple, fast and efficient, cross-platform, linux and win can be operated.

  2022-06-01 17:52:57 Views: 218
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  Mongodb simple installation

  In the installation record of centos6.4, download the mongodb installation package mongodb from http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-2.4.8.tgz"

  2022-06-01 17:52:56 Views: 238
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  MongoDB relationship-1-to-many embedded

  1. Check the database show dbs2. Use database use test3. View the collection show collections4 in the database. Add data to the collection (using the embedded method, you can embed the user address into the user's document) db.sit

  2022-06-01 17:52:49 Views: 216
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  A problem of hbase

  There is a problem with the hbase in the company's public network environment, and the phenomenon is that the hbase query is stuck. The error printed out is that the regionserver is not connected. It is found that the reason is that the ip bound when the public network machine starts regionserver is based on conf/regionse

  2022-06-01 17:52:48 Views: 267
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  How to modify the oracle time zone

  Change the time zone setting of Oracle: restart the Oracle database after alter database set time_zone='+8.00'; modification.

  2022-06-01 17:52:48 Views: 204
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  Oracle default user Summary

  There are two types of Oracle accounts: the necessary accounts, such as SYS/SYSTEM/SYSMAN, that store various applications, and the account that the user password describes the account ANONYMOUSANONYMOUS uses to access the ORACLEXMLDB knowledge base. CTXSYSC

  2022-06-01 17:52:48 Views: 207
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  Mysql client login configuration

  My.cnf profile parameter settings: [root@cacti ~] # head-7 / etc/ my.cnf [MySQL] prompt= "(\\ u@\\ h:\ R:\ m:\\ s) [\ d] >" pager= "l

  2022-06-01 17:52:47 Views: 273
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  Introduction to NoSQL (4)

  NoSQL introduction (4) Redis common operations Redis common operations-stringset key3 zsset key3 lisi / / the second assignment will overwrite setnx key3 wangwu / / return 0, then key

  2022-06-01 17:52:47 Views: 215