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This article mainly introduces how to achieve the mysql trigger, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Simple example of MySQL trigger

1. Grammar:

CREATE TRIGGER-the trigger must have a name, up to 64 characters, and may be followed by a delimiter. It is basically similar to the naming of other objects in MySQL.

{BEFORE | AFTER}-the trigger has a time setting for execution: it can be set before or after the event.

{INSERT | UPDATE | DELETE}-you can also set triggered events: they can be triggered during the execution of insert, update, or delete.

ON-A trigger belongs to a table: when an insert, update, or delete operation is performed on this table, the trigger is activated. We cannot schedule two triggers for the same event in the same table.

FOR EACH ROW-the interval at which the trigger executes: the FOR EACH ROW clause tells the trigger to perform an action every other row, rather than on the entire table.

-- the trigger contains the SQL statement to be triggered: the statement here can be any legal statement, including the compound statement, but the statement here is subject to the same restrictions as the function.

You must have considerable permissions to create a CREATE TRIGGER, and if you are already a Root user, that's enough. This is different from the standard of SQL.

2 simple trigger column

(1) View trigger show triggers

(2) Delete trigger drop trigger t_afterinsert_on_tab1

(3) now the simulation is to insert data into table student and back up to student1 table at the same time.

Create the required table

CREATE TABLE student (

Id varchar (11)

);

CREATE TABLE student1 (

Id varchar (11)

);

Create a trigger:

CREATE TRIGGER t_afterinsert_on_tab1

AFTER INSERT ON Student

FOR EACH ROW

BEGIN

Insert into Student1 (studentid,studentname) values (new.StudentID,new.StudentName)

/ / Note that new is directly followed by the field name of the table.

END

Test:

Insert into student (id) values ("1")

Select * from student

Select * from student1

Data synchronization can be found

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