How to prevent self-growth of MySQL self-growth fields when inserting data fails

Problem description: When MySQL set the self-growing field (note: A table can only set a self-growth field, may not be the primary key, but must be the key), if the insertion of data fails, then the self-growth field will still occupy the self-growth value, the data will be successfully inserted into the fault.

Cause: The self-increment is cached in the memory dictionary, and is allocated by first reserving and then inserting. Therefore, insert failure does not roll back the memory dictionary.

Workaround: In PHP program can add a piece of code, when inserting data fails, execute SQL statement reset Auto_increment value:

$sql = ALTER TABLE ' Tbname ' auto_increment=n;

Use function Mysqli_query ($sql) to execute SQL statements

How to prevent self-growth of MySQL self-growth fields when inserting data fails