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Description

Error 1359 in MySQL indicates that you are attempting to create a database trigger with a name that is already assigned to an existing trigger. This typically occurs when executing a `CREATE TRIGGER` statement for a trigger name that is not unique within its scope on the specified table.

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Error Message

Trigger already exists

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Known Causes

3 known causes

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Duplicate Trigger Creation Attempt

You might have accidentally executed a `CREATE TRIGGER` statement more than once, attempting to create the same trigger multiple times.

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Trigger Name Conflict

Another trigger with the exact same name already exists on the database table where you are trying to create the new trigger.

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Flawed Deployment Script

Automated deployment or migration scripts may attempt to create triggers without first checking if they already exist, leading to re-creation errors.

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Solutions

3 solutions available

1. Drop and Recreate the Trigger easy

Remove the existing trigger and then create it anew.

1

Identify the exact name of the trigger that is causing the error.

2

Use the `DROP TRIGGER` statement to remove the existing trigger.

DROP TRIGGER IF EXISTS trigger_name;

3

Execute the `CREATE TRIGGER` statement again with your trigger definition.

CREATE TRIGGER trigger_name
BEFORE INSERT ON your_table
FOR EACH ROW
BEGIN
    -- Your trigger logic here
END;

2. Check for Duplicates Before Creation medium

Query the information schema to see if the trigger already exists before attempting creation.

1

Before executing your `CREATE TRIGGER` statement, run a query to check if a trigger with the same name and for the same event/table already exists.

SELECT TRIGGER_NAME
FROM INFORMATION_SCHEMA.TRIGGERS
WHERE TRIGGER_SCHEMA = DATABASE()
  AND TRIGGER_NAME = 'your_trigger_name'
  AND EVENT_MANIPULATION = 'INSERT' -- Or UPDATE, DELETE, etc.
  AND EVENT_OBJECT_TABLE = 'your_table';

2

If the query returns a row, the trigger already exists. You can then choose to drop and recreate it (Solution 1) or skip the creation if it's not intended to be modified.

3

Alternatively, you can incorporate this check into a script that conditionally creates the trigger.

IF NOT EXISTS (
    SELECT 1
    FROM INFORMATION_SCHEMA.TRIGGERS
    WHERE TRIGGER_SCHEMA = DATABASE()
      AND TRIGGER_NAME = 'your_trigger_name'
) THEN
    CREATE TRIGGER your_trigger_name
    BEFORE INSERT ON your_table
    FOR EACH ROW
    BEGIN
        -- Your trigger logic here
    END;
END IF;

3. Verify Trigger Definition in Schema medium

Inspect the existing trigger's definition to ensure it's what you intend.

1

Use the `SHOW TRIGGERS` statement to list all triggers in your current database.

SHOW TRIGGERS;

2

Look for the trigger that is causing the error by its name. Examine its `Statement` column to see its current definition.

3

Compare this definition with the one you are trying to create. If they are identical and the trigger is functioning as expected, you might be encountering the error due to a script that is being run multiple times. In this case, consider using `DROP TRIGGER IF EXISTS` before creating.

4

If the existing trigger's definition is different from what you intend, you will need to drop it and recreate it with the correct definition.

DROP TRIGGER IF EXISTS trigger_name;
CREATE TRIGGER trigger_name ...

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Related Errors

5 related errors

MySQL Error 1359: Trigger Already Exists