Understanding the Error: "DETERMINISTIC, NO SQL, or READS SQL DATA" Declaration Requirement

When importing a database into MySQL, it's possible to encounter the following error:

1418 (HY000) at line 10185: This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you might want to use the less safe log_bin_trust_function_creators variable)

This error indicates that a defined function or stored procedure lacks one of the following declarations in its definition:

• DETERMINISTIC
• NO SQL
• READS SQL DATA

When binary logging is enabled in MySQL, these declarations are required to ensure data integrity and replication consistency.

Fixes for the Error

To resolve this issue, you can utilize one of two methods:

1. Enable the log_bin_trust_function_creators Variable:

   • In the MySQL console, execute the following command:

     SET GLOBAL log_bin_trust_function_creators = 1;

   • Alternatively, add the following to your MySQL configuration file (e.g., mysql.ini):

     log_bin_trust_function_creators = 1;

   Enabling this setting allows functions without explicit declarations to be executed during binary logging.

2. Add the Appropriate Declaration to the Function or Procedure:

   • For functions that always produce the same output for the same input parameters, use the DETERMINISTIC declaration. For example:

     CREATE FUNCTION my_function() DETERMINISTIC
     BODY
      -- Your function logic
     END

   • For functions that do not contain any SQL statements, use the NO SQL declaration.

     CREATE FUNCTION my_function() NO SQL
     BODY
      -- Your function logic
     END

   • For functions that only read data from the database, use the READS SQL DATA declaration.

     CREATE FUNCTION my_function() READS SQL DATA
     BODY
      -- Your function logic
     END

Understanding Deterministic Function Declarations

Non-deterministic functions can modify data or use unpredictable inputs, leading to different results for the same input parameters. As such, it's important to accurately declare function behavior to optimize performance and ensure data integrity.

The MySQL documentation provides a comprehensive guide to the various function and stored procedure function declaration options, allowing you to make informed decisions for each function. Misdeclarations can impact execution plans and affect performance.