How to Combine MySQL Insert and Update Triggers to Avoid Code Duplication?

Combining Insert and Update Triggers to Avoid Code Duplication

In certain scenarios, it may be desirable to trigger a specific action when data is either inserted or updated within a database table. The MySQL database system allows for the creation of triggers that execute customizable actions upon specific events, such as inserts or updates. However, there is no direct way to combine insert and update triggers into a single rule.

One potential solution is to create two separate triggers, one for insert events and one for update events. However, this approach leads to code duplication if the actions to be executed are identical for both triggers.

To overcome this issue, it is possible to extract the common code into a stored procedure and have both triggers call this procedure. By doing so, you can avoid code repetition while still achieving the desired functionality. Here's an example of how to accomplish this:

1. Create a stored procedure to encapsulate the common code:

CREATE PROCEDURE my_common_procedure()
BEGIN
    -- Insert or update logic here
END //

2. Create the insert trigger:

CREATE TRIGGER my_insert_trigger
AFTER INSERT ON `table`
FOR EACH ROW
BEGIN
    CALL my_common_procedure();
END //

3. Create the update trigger:

CREATE TRIGGER my_update_trigger
AFTER UPDATE ON `table`
FOR EACH ROW
BEGIN
    CALL my_common_procedure();
END //

In this example, both triggers execute the same code by calling the my_common_procedure. This approach provides a clean and efficient way to handle insert and update events without repeating code.

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