Introduction and Operation of MySQL View

1. Preparations Create two tables balance (balance table) and customer (customer table) in MySQL database and insert data. create table customer( id int(10) primary key, name char(20) not null, role char(20) not null, phone char(20) not null, sex char(10) not null, address char(50) not null )ENGINE=InnoDB DEFAULT CHARSET ...

Posted by shaunrigby on Thu, 09 May 2019 05:42:03 +0200

Basic knowledge of Java ——JDBC

Author: Nobody Source: CSDN Original text: https://blog.csdn.net/h1025372645/article/details/89191301 JDBC Java DataBase Connectivity,java database connection, in order to reduce the difficulty of operating data, java provides jdbc, according to the characteristics of java object-oriented, many operations are encapsulated. JDBC ...

Posted by arctushar on Wed, 08 May 2019 21:57:03 +0200

Constructing an application dApp of Etherfang+IPFS+React.js

Why do we build this? It is very expensive to store a large amount of data on the block chain of Taifang. According to the Yellow Paper of ETF, it is about 20,000 gas, 256 bit/8 bytes (1 word). Based on 02/28/2018 gas price is 4 gwei/gas. Please refer to: https://ethgasstation.info Know the current price. Each transaction has 8 bytes of 20,000 ...

Posted by thepreacher on Wed, 08 May 2019 18:00:02 +0200

[Reload, Organize] Turn on archive mode, archive log is full

At ORACLE10g and 11g versions, the default log archive path for ORACLE is the flash-back recovery area ($ORACLE_BASE/flash_recovery_area).ORACLE has a limitation on this path: it only has 2G of space by default, and it is not only the default path for archive logs, but also the default address for backup files and flash back lo ...

Posted by maheshb on Wed, 08 May 2019 04:35:03 +0200

NEO400J Level Full-Text Index Construction Optimization

NEO400J Level Full-Text Index Construction Optimization 1. Scale of data volume (level 100 million) 2. Ways to Build Indexes 3. Exceptions Occurring in Index Building IV. Code optimization for full-text index 1,Java.lang.OutOfMemoryError 2. When accessing a database 3. Optimizing scheme 4. Optimize Code 5. Perform efficiency ...

Posted by lisa007 on Tue, 07 May 2019 12:10:06 +0200

Hand-in-hand teaching you how to use ORM database gracefully in Flutter project--Part II

A orm database Flutter plugin. I posted an article earlier. Hand-in-Hand Teaching You Elegant Use of ORM Database in Flutter Project Many people also put forward some valuable suggestions on consulting and using, saying that they do not want to write lua, which is not elegant enough, but also increases the cost of learning. On reflection, it is ...

Posted by hijack on Tue, 07 May 2019 05:00:05 +0200

Redis Learning Cluster

Redis Learning Cluster Preface In the first place, we learned the basic operation of Redis, the use of Jedis and the persistence scheme of Redis. Next, we learned the cluster management of Redis. copy When data is stored on a server, if the server hangs up, the data will be lost, so Redis provides the function of replicati ...

Posted by NTM on Tue, 07 May 2019 04:25:05 +0200

kubernetes event reflector

kubernetes event reflector kubernetes event reflector ListWatcher interface ListWatch Implementing ListWatcher Interface Informer using ListWatch Reflector Reflector type definition Functions to create Reflector objects Run() method ListAndWatch() method controller using Reflector Run() method processLoop() metho ...

Posted by Neumy on Mon, 06 May 2019 23:35:04 +0200

Redis 7000w+ keys && 16G memory 100% repair experience

cause We always use redis of Aliyun. We are not a high concurrent application. We mainly use redis as distributed locks and a small amount of caches. It hardly needs maintenance. Yesterday afternoon, we suddenly received an alarm email. On-line redis memory is used 100% and instantaneous nerve tension sensation is confirmed by console.This is a ...

Posted by jim_de_bo on Mon, 06 May 2019 15:00:04 +0200

PostgreSQL Heap Only Tuple - HOT (Reducing Index Writing IO Enlargement Introduced by UPDATE)

Label PostgreSQL , Heap Only Tuple , HOT background PostgreSQL's current default storage engine generates a new version in the heap when updating records. The old version needs to recycle all index POINT associated with this version before it needs to recycle the old version after VACUUM is used. The KEY of the index of PG is the value of th ...

Posted by Goins on Mon, 06 May 2019 12:45:03 +0200