MySQL -- Common Functions

Character function Function name Effect CONCAT() Character Connection CANCAT_WS("delimiter", "value", "value",...) Character join with specified delimiter FORMAT() NumberFormatter LOWER() Convert to lowercase UPPER() uppercase LEFT() Interception from the left RIGHT() Interception ...

Posted on Fri, 14 Jun 2019 13:49:03 -0700 by DRTechie

Handwritten Mybatis, which needs to be adjusted later

Reference Blog https://blog.csdn.net/Kurozaki_Kun/article/details/81482212 Personal understanding 1 Read the Mybatis configuration file 2 Database Connection Information 3 Read Mapper.xml file 4.1. Encapsulate the Added, Deleted and Revised Node Information into a MapperInfo 52. Create a Map Storage (interface full path name + met ...

Posted on Thu, 13 Jun 2019 10:57:57 -0700 by wompas.dub

easyui implements tree menu and Tab functions

One: three common front-end ui frameworks In the beginner's introductory state, there are three common front-end frameworks and they all have their own official websites: 1.easyui: official website (http://www.jeasyui.net/) jquery-based set of user page plug-ins provides corresponding functions for some interactive js. Developers do not need ...

Posted on Tue, 11 Jun 2019 12:18:28 -0700 by megaalf

Hibernate uses queries

Summary of Hibernate Query Common Methods Common Query Methods Navigation Object Graph Retrieval: Navigate to other objects, such as queries for related objects, based on the loaded objects. OID retrieval method: Retrieve an object by its OID.Get load HQL retrieval method: use special HQL query interface and object-oriented HQL query lan ...

Posted on Tue, 11 Jun 2019 11:31:39 -0700 by Nilanka

Massive Extreme Speed Multidimensional Retrieval of Time, Space and Objects-Best Practice of RDS PostgreSQL in Aliyun

Label PostgreSQL, Time, Space, Object Attributes, Multidimensional Retrieval, Massive, Spatial Index, Data Partition, Block Index BRIN, Multilevel Index, GIN Inverted Index, JSON Index, Multilevel Index, Multilevel Index, Multi-Index Scan Merge, Bitmap And Bitmap Or, Physical Scan, ctid Scan, Interect, Index, Partition Index, Partition Index ...

Posted on Tue, 11 Jun 2019 11:00:20 -0700 by Joseph Witchard

How MySQL checks inconsistencies between master and slave data and continues to synchronize

The two MySQL tables are inconsistent with each other, but the synchronization is still going on normally. Later, I realized that this problem (skip, or inconsistent state at the beginning of the build) should be repaired. Let's see how percona-toolkit fixes this situation. Verification: Main database: 192.168.100.8 3306 Congku: 192.168.100.1 ...

Posted on Tue, 11 Jun 2019 10:49:48 -0700 by jharbin

Two implementations of Greenplum aggregation function: HashAggregate and GroupAggregate

Postgresql/Greenplum data base There are two ways to implement aggregation functions: HashAggregate and GroupAggregate. We now analyze the differences between the two aggregations and their application scenarios through a simplest sql.       select count(1) from pg_class group by oid; 1. Comparisons of two implementation algorithms: Ha ...

Posted on Sun, 09 Jun 2019 16:30:01 -0700 by hagman

Optimization of connect by statement in oracle

In many applications, there will be tables that resemble organizational structures, and organizational tables are typically hierarchical (with no looping nodes).So when controlling data permissions through an organization, many people like to get organizational information through connect by and then filter the target data. In some cases, this ...

Posted on Sat, 08 Jun 2019 15:47:36 -0700 by bullchina

Introduction to yii2 Queue shmilyzxt/yii2-queue

It feels good to see a post about queues in the yii2 forum. http://www.yiichina.com/extension/1084 (Note: SendMail is wrongly written as SendMial, be careful when pasting.) I think it's good to use it, so I suggest you take a look at how queues work. shmilyzxt/yii2-queue Simple explanation: In the advanced version of yii2 that I use, let's ...

Posted on Sat, 08 Jun 2019 13:41:08 -0700 by zrueda

Using otter to realize bidirectional synchronization of MySQL across computer rooms

Using otter to realize bidirectional synchronization of MySQL across computer rooms Workflow Environmental Science target Noun Interpretation install To configure Configure mysql Import manager system table Importing System Table Dependent on node Synchronization Algorithms Management Configuration Add zookeeper host Add node add ...

Posted on Fri, 07 Jun 2019 19:30:36 -0700 by Sykoi