Database and table building
view the database
sentence
show datebases;
-- View all databases
effect
[take mine as an example, the following are]
mysql> show databases; ±-------------------+ | Database | ±-------------------+ | information_schema | | mysql | | performance_schema | | sqlfortextbook | | studb | | sys | ±------------- ...
Foreword:
After learning from the previous article, we know that binlog will record all executed DDL and DML statements in the database (except data query statements select, show, etc.). Note that the operations of all libraries are recorded by default, so if we have alternative requirements, such as only allowing a certain library to record b ...
Posted by work_it_work on Tue, 03 May 2022 21:58:30 +0300
2. Operation database
2.1 operation database
2.2 column type of database
numerical value
tinyint very small data 1 bytesmallint smaller data 2 bytesmediumint medium size 3 bytesint standard integer 4 bytesbigint larger datafloat floating point number 4 bytesdouble floating point number 8 bytesFinancial calculation of floating point num ...
Posted by grumpy on Tue, 03 May 2022 19:40:00 +0300
This article mainly contains the advanced part of the 72 questions in the SQL article, which is a must-tested question in the interview. It mainly includes the more difficult level (18 questions) and the difficult level (4 questions). The questions are more complicated, and my answer may not be the best solution. , Welcome everyone to correct m ...
Posted by glcarlstrom on Mon, 02 May 2022 21:55:06 +0300
1, Introduction to mycat
MyCat is an open source distributed database system. It is a server that implements MySQL protocol. Front end users can regard it as a database agent and access it with MySQL client tools and command line. Its back end can communicate with multiple MySQL servers with MySQL native protocol or with most mainstream databas ...
Posted by versatilewt on Mon, 02 May 2022 19:49:08 +0300
1, What is JDBC
When it comes to JDBC, we should first think of the 13 specifications in Java. One of them is JDBC. What is it and what is its use?
Let's take a look at Baidu Encyclopedia first
In short, it is the method of connecting the database with Java, but we all know that the Java language is developed and maintained by Oracle company, ...
Create test library
Create the database and set the encoding to utf8
create database zabbix character set utf8 collate utf8_bin;
Create user
Create user and set password
create user 'zabbix'@'localhost' identified by '<password>';
to grant authorization
Let zabbix users have all permissions of zabbix Library (local)
grant all pr ...
Posted by goldfiles on Mon, 02 May 2022 09:19:53 +0300
5.mysql transactions and indexes
**Business**
Execute a group of sql statements in the same batch
If an sql error occurs, all the sql in the batch will be cancelled
mysql transaction processing only supports innoDB and BDB data table types
ACID principle of transaction
Atomic ity
All operations in the whole transaction are either complet ...
Posted by rid243 on Mon, 02 May 2022 07:52:02 +0300
A transaction is a user-defined sequence of database operations. These operations are either done or not done at all, and are an inseparable unit of work.
Based on the atomicity, consistency, isolation and persistence characteristics of transactions, related data operations can be defined into a transaction.
If no exception occurs during the ...
Posted by wblati on Sat, 30 Apr 2022 23:02:23 +0300
Source code acquisition: download from "resources" on the blog home page!
Project introduction
The warehouse management system is divided into three modules: basic management, warehouse management and system management. There are sub modules under each module. functional module
1, Basic management
1. Customer management Custome ...
Posted by tsigo on Sat, 30 Apr 2022 21:52:16 +0300