MySQL trigger creation trigger
MySQL trigger creation trigger
Triggers play a very important role in the database system development process, such as preventing harmful data from being entered into the database. You can change or cancel the execution of insert, update, and delete statements and monitor changes in data in the database in a session.
Then we have previously introduced several articles about the application of MySQL views "The application of MySQL views - Creating views" "The application of MySQL views - Modifying views 》 and "Application View of MySQL View", then our article will mainly introduce MySQL triggers~
If the user intends to implement a certain action in the database through a trigger To listen, you should first create a trigger, which is created under the "Command Prompt".
Technical Points
The format of a MySQL database creation trigger is as follows:
create trigger <触发器名称>
{ before | after}
{insert | update | delete}
on <表名>
for each row
<触发器SQL语句>create trigger { before | after}: Used to specify whether to trigger before the insert, update or delete statement is executed or after the statement is executed. on For each row: The execution interval of the trigger, for each row notifies the trigger to perform an action every other row, rather than once for the entire table. Implementation process (1) Create the data table tb_test under the "Command Prompt". The code is as follows: (2) Convert the newline mark to "//". The code is as follows: (3) Create a trigger to make the content of field t_name "mrsoft" no matter what data the user adds to table tb_test. The code is as follows: (4) Add a record to table tb_test and view the added results. The code is as follows: Then we enter the above implementation process step by step in the "Command Prompt", and the output result is as follows: About We have just introduced the creation of MySQL triggers here. Isn’t it very simple? I believe everyone can master it quickly. Then our next article will continue to introduce MySQL triggers. For details, please read "MySQL Triggers" View trigger》! 【Recommended related tutorials】 1.【MYSQL online free video tutorial】 2. Recommended related video courses : "Power node mysql basic video tutorial" The above is the detailed content of MySQL trigger creation trigger. For more information, please follow other related articles on the PHP Chinese website! AI-powered app for creating realistic nude photos Online AI tool for removing clothes from photos. Undress images for free AI clothes remover Swap faces in any video effortlessly with our completely free AI face swap tool! Easy-to-use and free code editor Chinese version, very easy to use Powerful PHP integrated development environment Visual web development tools God-level code editing software (SublimeText3) MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables. MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen Apache connects to a database requires the following steps: Install the database driver. Configure the web.xml file to create a connection pool. Create a JDBC data source and specify the connection settings. Use the JDBC API to access the database from Java code, including getting connections, creating statements, binding parameters, executing queries or updates, and processing results. MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions. The process of starting MySQL in Docker consists of the following steps: Pull the MySQL image to create and start the container, set the root user password, and map the port verification connection Create the database and the user grants all permissions to the database The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed. Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests. The key to installing MySQL elegantly is to add the official MySQL repository. The specific steps are as follows: Download the MySQL official GPG key to prevent phishing attacks. Add MySQL repository file: rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm Update yum repository cache: yum update installation MySQL: yum install mysql-server startup MySQL service: systemctl start mysqld set up booting: used to specify the table name that responds to the trigger.
create table tb_test(t_id varchar(20),t_name varchar(20))
delimiter //
create trigger test_tri
before insert on tb_test
for each row
set new.t_name='mrsoft'
insert into tb_test(t_id,t_name) values('mr0001', '123')//
select * from tb_test
Hot AI Tools
Undresser.AI Undress
AI Clothes Remover
Undress AI Tool
Clothoff.io
Video Face Swap
Hot Article
Hot Tools
Notepad++7.3.1
SublimeText3 Chinese version
Zend Studio 13.0.1
Dreamweaver CS6
SublimeText3 Mac version
Hot Topics
MySQL: An Introduction to the World's Most Popular Database
Apr 12, 2025 am 12:18 AM
MySQL's Place: Databases and Programming
Apr 13, 2025 am 12:18 AM
How to connect to the database of apache
Apr 13, 2025 pm 01:03 PM
Why Use MySQL? Benefits and Advantages
Apr 12, 2025 am 12:17 AM
How to start mysql by docker
Apr 15, 2025 pm 12:09 PM
MySQL's Role: Databases in Web Applications
Apr 17, 2025 am 12:23 AM
Laravel Introduction Example
Apr 18, 2025 pm 12:45 PM
How to install mysql in centos7
Apr 14, 2025 pm 08:30 PM
