# Limitations and considerations

The following limitations apply:

* Due to the way Microsoft Azure Database for MySQL operates, when loading data to a Microsoft Azure Database for MySQL target during a Full Load task, duplicate key errors will not be reported to the logs.

* When updating a column's value to its existing value, a zero rows affected is returned from Microsoft Azure Database for MySQL (unlike Oracle and Microsoft SQL Server that perform an update of one row). This generates an entry in the `attrep_apply_exceptions` control table and the following warning:

  ` Some changes from the source database had no impact when applied to the target database. See attrep_apply_exceptions table for details.  `

* If you need to replicate 4-byte emoji characters, the target schema character set must be set to utf8mb4.