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Description

MySQL Error 1465 indicates an attempt to create a database trigger on a table that belongs to a system schema (e.g., `mysql`, `information_schema`, `performance_schema`, `sys`). MySQL explicitly prevents this operation to safeguard the integrity and stability of its internal components. This error occurs when a `CREATE TRIGGER` statement targets one of these protected system tables.

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Error Message

Triggers can not be created on system tables

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Known Causes

3 known causes

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Targeting MySQL System Database

You attempted to create a trigger on a table within the `mysql` database, which stores user privileges and server configuration, and is protected from such modifications.

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Targeting Internal Schema Tables

The trigger creation statement specified a table in `information_schema`, `performance_schema`, or `sys` databases, which are read-only or system-managed and cannot have triggers.

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Incorrect Table Selection

The intended table for the trigger was mistakenly identified as a user-defined table when it was actually a system-managed table, leading to the error.

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Solutions

3 solutions available

1. Identify and Remove Incorrect Trigger easy

Locate and drop the trigger that is attempting to attach to a system table.

1

Connect to your MySQL server using a client like the MySQL command-line client, MySQL Workbench, or DBeaver.

2

List all existing triggers to identify the one causing the error. System tables are typically in the `mysql` database.

SHOW TRIGGERS;

3

Examine the output for any triggers associated with tables in the `mysql` database. The error message usually indicates the table name. If you find such a trigger, drop it.

DROP TRIGGER IF EXISTS trigger_name;

4

Replace `trigger_name` with the actual name of the trigger you identified in the previous step.

2. Review and Correct Trigger Creation Statement medium

Analyze the `CREATE TRIGGER` statement to ensure it targets a user-defined table, not a system table.

1

Locate the SQL script or command where the trigger was created.

2

Carefully review the `ON table_name` clause in your `CREATE TRIGGER` statement.

CREATE TRIGGER trigger_name BEFORE INSERT ON table_name FOR EACH ROW ...

3

Ensure that `table_name` refers to a table in your application's database and not a table within the `mysql` system database (e.g., `mysql.user`, `mysql.db`, `mysql.tables`).

4

If the trigger was intended for a user table, correct the `table_name` to the correct user-defined table and re-execute the `CREATE TRIGGER` statement.

CREATE TRIGGER trigger_name BEFORE INSERT ON your_user_table FOR EACH ROW ...

3. Isolate Trigger Logic to a User Table advanced

If the trigger logic is essential, move it to a user-defined table or implement it differently.

1

Understand the purpose of the trigger that is failing. What functionality does it aim to provide?

2

Determine if this functionality can be achieved by attaching a trigger to a different, user-defined table in your schema.

3

If so, create a new user-defined table that is relevant to the functionality. For example, if the trigger was intended to log changes to user authentication, create a `user_audit_log` table.

CREATE TABLE user_audit_log (
    log_id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT,
    action VARCHAR(50),
    timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

4

Rewrite the trigger logic to operate on this new user-defined table. This might involve creating a new trigger on the user-defined table or modifying an existing one.

CREATE TRIGGER log_user_change
AFTER UPDATE ON mysql.user
-- This example is illustrative and would likely need to be modified to target a user table.
FOR EACH ROW
BEGIN
    -- Logic to insert into user_audit_log
END;

5

Alternatively, consider if the desired functionality can be implemented using stored procedures, application-level logic, or scheduled events instead of triggers on system tables.

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Related Errors

5 related errors

MySQL Error 1465: Triggers on System Tables Forbidden