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Business scenario: balance shared by different business systems, hjmallind_user and ims_cjdc_user two tables have different balance fields, but share the balance value. Trigger definition: DROP TRIGGER IF EXISTS `test-up_ds_wallet`; CREATE  TRIGGER `test-up_ds_wallet` AFTER UPDATE ON `ims_cjdc_user`      FOR EACH ROW      BEGIN         DECLAR ...

1. Services 1.1 concept of transaction Transaction: a transaction consists of one or more SQL statements in a single unit, in which each MySQL statement is interdependent. The whole single cell is an inseparable whole. If an SQL statement in the cell fails or generates an error, the whole cell will be rolled back. All affected data will be re ...

1. What are integrity constraints? In order to prevent non-conforming data from being stored in the database, MySQL provides a mechanism to check whether the data in the database meets the specified conditions when users insert, modify and delete the data, so as to ensure the accuracy and consistency of the data in the database. This mechanism ...

Foreword: At this stage of high concurrency, MySQL must be read-write separated. In fact, most Internet websites or App s read more and write less. So in this case, if you write a master library, but the master library hangs multiple slaves and reads from multiple slaves, can't that support higher read concurrency pressure? 1. MySQL Read-Write ...

Preface Every time I open the learning video to watch, I always want to organize and record it in the future, but there are always some big and small reasons (well, only lazy) that cause this wonderful dream to be broken. Ha-ha, I don't know what kind of mood trend it is today. I opened it and wrote this sentence, but I hope I can really ...

1, The first is the one click installation and uninstallation commands of MySQL (you can choose any one to execute) (1) Installation command sudo apt-get install mysql (Download the latest version) sudo apt install mysql-server mysql-client (2) Uninstall command: if there is a problem, reinstall MySQL for use, such as forgetting the initial ...

catalogue 1. Introduction to JDBC 2. Common API components 3. JDBC usage 3.1 introducing MySQL driver 3.2 jdbc connection database programming Programming steps 4. Common API usage 4.1 Connection interface: the object of database connection 4.2 Statement interface: used to execute SQL statements 4.3 ResultSet(): returns the result set ...

Preface: Hello, ladies and gentlemen, I'm running like a snail rz. Of course you can call me Snail Jun. I'm a beginner who has studied Java for more than half a year. At the same time, I have a great dream that I will become an excellent Java architect one day. This Mybatis Basic Learning series is used to record the whole process of my lea ...

1, CTE characteristics Starting from SQL Server 2005, syntax support for CTE(Common Table Expression) is provided. CTE is a temporarily named result set defined in SELECT, INSERT, UPDATE or DELETE statements. At the same time, CTE can also be used in the definition of views. A reference to itself can be included in the CTE, so this expression i ...

Deploy Springboot+Mysql project with Docker Compose In the last article Spring Boot(Maven)+Docker packaging In, we implemented one click packaging and deployment of the Springboot project source code as a Docker service. In the above, if our Springboot project wants to connect to the database, it must be connected to the public IP. This paper ...