Introduction of master and slave
What is master-slave?
MySQL master-slave replication is one of its most important functions. Master-slave replication refers to that one server acts as the master database server and another or more servers act as the slave database server, and the data in the master ...
Posted by grimz on Fri, 19 Jun 2020 05:48:13 -0700
SELECT pf1001.attrId, attrCode, attrName,
when '04' THEN CONCAT('product-',(select productName from pf1003 where productId= pf1001.scopeId))
WHEN '03' THEN CONCAT('Product line-',(select productLineName from pf1004 where productLineId= pf1001.scopeId))
WHEN '02' THEN CONCAT( ...
Posted by philwhite on Thu, 18 Jun 2020 03:29:30 -0700
Finish MySQL in half a day (all)
Finish MySQL (all) 1 in half a day
The blogger uses MySQL version 8.0, and the storage engine is InnoDB. We don't explain InnoDB in detail here. If necessary, we recommend you to know This article Blog (or Baidu) https://www.jianshu.com/p/519fd7747137
3A. Add, delete, ...
Posted by pella.d on Wed, 17 Jun 2020 23:46:05 -0700
Previous writing is too messy, turn it out and reorganize it
Small Catalog Series:
(1) Getting started with MySQL is not a big problem
(1) introducing constraints
(1) Where do constraints occur?
To explain constraints, you need to know where and why constraints are used.
The SQL language completes the definitio ...
Posted by gacon on Tue, 16 Jun 2020 18:12:15 -0700
Python 3.7 learning notes 27 context manager
Input and output of files, connection and disconnection of database are common resource management operations. Because of limited resources. In such a scenario. If these resources are used but not released. It will cause resource leakage. Light makes the ...
Posted by mcmuney on Mon, 15 Jun 2020 19:33:05 -0700
Database integrity: prevent non semantic and incorrect data from entering the database;
Database security: prevent illegal users from intruding into the database and illegally accessing the database data.
5.1 entity integrity PRIMARY KEY
Entity integrity definition: single attribute - column level, tabl ...
Posted by pillarofautumn on Mon, 15 Jun 2020 01:01:57 -0700
The label used to loop the container forEach, see the example
The properties of foreach element mainly include item, index, collection, open, separator, close.
item: the alias of the element iteration in the collection,
Index: the index when the elements in the collection iterate
open: in the ...
Posted by mebar3 on Mon, 15 Jun 2020 00:25:08 -0700
Privilege management is a necessary module in almost every system. If the project development needs to realize the right management every time, it will undoubtedly waste the development time and increase the development cost. As a result, the caspin library appears. Caspin is a powerful and efficient access control library. I ...
Posted by topsub on Sun, 14 Jun 2020 18:44:09 -0700
Oracle trail learning experience
Annotate a custom column name
Incoming parameters: field name and annotation
create or replace procedure csp_col_comment (
p_column_name varchar, --Field name
p_Title varchar, --field comment
p_RetVal Out integ ...
Posted by techjosh on Sat, 13 Jun 2020 23:52:50 -0700
In daily work, we often need to develop reports or count the percentage and total of some data. At this time, the following functions can solve the problem quickly. They have fewer sql statements and better performance. The figure below shows the results of our statistics.
Posted by NEWDAY on Sat, 13 Jun 2020 23:15:50 -0700