Student table: Chart of Accounts: Achievement Sheet: Data modification and deletion: 1. Renew the address of Xi'an City to Xi'an Science and Technology Second Road 2. Modify the email of S1001 to an empty string 3. Update the name of the second course to java basics, with 60 hours and a second grade class 4. Increase the S1001 and course numbe ...
Posted by kiss-o-matic on Fri, 12 Nov 2021 11:59:02 -0800
select Query list
from Table 1 alias [connection type]
join Table 2 aliases
on Connection conditions
[where [filter criteria]
[group by [grouping]
[having [filter criteria]
[order by Sort list]
Classification: inner connection (★): inner External connection Left outer (★): left [outer] Right outer (★): right [outer] fu ...
Posted by thomas777neo on Thu, 11 Nov 2021 01:08:44 -0800
Go operation Mysql database
There is a database/sql package in go, which defines the methods of connecting and operating the database, And the native supports connection pool, which is concurrent and safe. This standard library has no specific implementation, but lists the specific contents that need to be implemented by a third-party libra ...
Posted by malec on Wed, 10 Nov 2021 21:56:03 -0800
After the database is built, we can then create tables that actually store data. When creating a table, you first need to describe what the table looks like, what columns it has, what types of data these columns are used to store, etc. this description of the table is called the structure or definition of the table. With the structure of the ta ...
Posted by madmega on Wed, 10 Nov 2021 16:34:38 -0800
This article is reproduced from the official account of "good future technology". The use of Flink CDC 2 is introduced in the case of Flink SQL, and the core design of CDC is interpreted. The main contents are as follows:caseCore designCode explanationGitHub address https://github.com/apache/flinkWelcome to like Flink and send star~In ...
Posted by murdocsvan on Wed, 10 Nov 2021 15:35:58 -0800
When the client connects to the MySQL server, it must provide valid identity authentication, such as user name and password. When the user performs any database operation, the server will verify whether the user has corresponding permissions. For example, SELECT permission is required for query tables and DROP permission is required for deletin ...
Posted by dreamer on Wed, 10 Nov 2021 12:52:00 -0800
I. preparation before installation
1. Check whether mysql has been installed and execute the command
[root@localhost /]# rpm -qa | grep mysql
From the execution results, we can see that mysql-libs-5.1.73-5.el6 has been installed_ 6.x86_ 64. Execute the delete command
[root@localhost /]# rpm -e --nodeps mysql-libs-5.1.73-5.el6_6.x86_64
Posted by MalikBB on Wed, 10 Nov 2021 10:00:57 -0800
In mysql, a set of tables is called a database. The MySQL server manages several databases. There can be several tables under each database. Draw a diagram as follows:
When we just installed MySQL, many databases and tables were built in it. We can use the following command to see which databases are available:
Posted by vasse on Wed, 10 Nov 2021 09:52:42 -0800
DB: databaseDBMS: Database Management SystemSQL: Structured Query Languagedatabasedata sheetfield
After mysql is successfully installed, common commands:
mysql [-h host ip -p port] - u user name - p enter enter password to log inshwo databases; Display all databases after successful loginuse database name; Open data ...
Posted by richo89 on Wed, 10 Nov 2021 00:30:09 -0800
The main purpose of backup is disaster recovery. Backup can also test applications, rollback data modification, query historical data, audit, etc.
Log plays an important role in backup and recovery.
1, MySQL log
The default location of MySQL logs is / usr/local/mysq ...
Posted by irbrian on Mon, 08 Nov 2021 16:44:35 -0800