Re: MySqlConnectionStringBuilder CharacterSet Property

[Jose Ramirez Ruiz]

Hi Ben,

The documentation text you quoted appears to be for the third-party MySqlConnector library, not Oracle’s MySql.EntityFrameworkCore / MySql.Data provider.

With MySQL Connector/NET, CharacterSet is a supported connection option. If you leave it blank, the connection uses the server/session default character set. If that default is not utf8mb4, Unicode characters outside that character set can be converted incorrectly, often appearing as question marks.

Setting:

CharacterSet = "utf8mb4"

is therefore a valid workaround/recommendation when your application stores Unicode text, provided the target database/table/columns also use utf8mb4.

To see what the session is actually using, query it after opening the connection:

SELECT
@@character_set_client,
@@character_set_connection,
@@character_set_results,
@@collation_connection;

or:

SHOW SESSION VARIABLES LIKE 'character_set_%';
SHOW SESSION VARIABLES LIKE 'collation_%';

The MySqlConnectionStringBuilder.CharacterSet property only shows what you explicitly put in the connection string. If it is blank, it does not mean the active MySQL session has no character set; it means the provider will use the server/session default.

You should also verify the schema:

SHOW FULL COLUMNS FROM your_table;

or check INFORMATION_SCHEMA to confirm that the database/table/columns are utf8mb4.

====================================
Jose Ramirez
MySQL Team