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Description

This error indicates an attempt to execute an SQL statement or construct that is explicitly forbidden within the context of a MariaDB stored function or trigger. These routines have specific restrictions to maintain data integrity, ensure predictable behavior, and prevent unintended side effects on the calling transaction or database schema.

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Error Message

%s is not allowed in stored function or trigger

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Known Causes

4 known causes

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Using DDL Statements

Stored functions and triggers are not permitted to execute Data Definition Language (DDL) statements such as CREATE, ALTER, or DROP database objects.

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Transaction Control Statements

Statements like COMMIT, ROLLBACK, or SAVEPOINT are forbidden as they can interfere with the transaction initiated by the caller.

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Statements Returning Result Sets

SQL statements that produce a result set, such as a bare SELECT query, are not allowed in contexts expecting a scalar return or no direct output.

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Dynamic SQL Execution

Using PREPARE and EXECUTE for dynamic SQL is often restricted within stored functions and triggers due to potential security and predictability concerns.

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Solutions

3 solutions available

1. Remove or Replace Disallowed Statement easy

Identify and remove or replace the statement causing the error.

1

Examine the stored function or trigger code. The error message will typically indicate the problematic statement (e.g., 'LOAD DATA INFILE', 'INSERT ... ON DUPLICATE KEY UPDATE').

2

If the disallowed statement is essential, consider if it can be refactored. For example, instead of 'INSERT ... ON DUPLICATE KEY UPDATE', you might use a combination of 'SELECT' and 'INSERT' or 'UPDATE' based on the existence of the record.

3

If the disallowed statement is not critical, simply remove it from the stored routine.

ALTER FUNCTION my_function DETERMINISTIC BEGIN -- Original disallowed statement -- New logic END;

4

Recompile or re-create the stored routine after making the changes.

DELIMITER //
CREATE OR REPLACE FUNCTION my_function() RETURNS INT
BEGIN
  -- ... your modified logic ...
  RETURN 0;
END //
DELIMITER ;

2. Use an Alternative Approach medium

Find a different method to achieve the same result without using disallowed statements.

1

Understand the purpose of the disallowed statement. For example, if it's 'LOAD DATA INFILE', you might need to read the file data in your application code and then insert it row by row or in batches using 'INSERT' statements within the stored routine (if permitted).

2

If the disallowed statement involves modifying data in a way that's not permitted (e.g., certain DDL statements in triggers), consider performing those operations outside the stored routine, perhaps in a separate stored procedure that can be called from the application.

3

Implement the alternative logic in your stored routine and test thoroughly.

3. Execute Disallowed Statements Outside the Stored Routine easy

Move the problematic operation to be executed by the client application.

1

Identify the disallowed statement in your stored routine.

2

Remove the disallowed statement from the stored function or trigger.

ALTER FUNCTION my_function BEGIN -- Removed disallowed statement -- Other logic END;

3

Modify your client application code (e.g., Python, PHP, Java) to execute the disallowed statement directly. For instance, if it was 'LOAD DATA INFILE', your application would now handle reading and inserting the data.

import mysql.connector

cnx = mysql.connector.connect(...)
cursor = cnx.cursor()

# Instead of calling a function that used LOAD DATA INFILE
with open('data.csv', 'r') as f:
    for line in f:
        values = line.strip().split(',')
        cursor.execute("INSERT INTO my_table (col1, col2) VALUES (%s, %s)", values)

cxn.commit()
cursor.close()
cxn.close()

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Related Errors

5 related errors

MariaDB Error 1336: Disallowed Statement in Stored Routines