`MySqlDataReader.GetGuid` returns incorrect UUID

Question

I generate UUIDs by using UUID_TO_BIN(UUID(), true) and storing them as BINARY(16).

However, when fetching the values:

var uuid = dataReader.GetGuid(name);
Console.WriteLine(uuid.ToString());

I do get an uuid string printed, but it is not the same string as when running SELECT BIN_TO_UUID("col") on the column.

What am I doing wrong?

• I tried setting OldGuids in connection string to true but still got the same incorrect uuid back.
• I am using MySql.Data .NET Connector version 8.3.0. And server is version 8.0.36.
• Reason I'm using UUID_TO_BIN(UUID(), true) and storing them as BINARY(16) is that, according to my readings, I thought this was the most efficient way to store uuids and using them as primary keys.

Thanks

Additional Info

Operation	Returns
GetGuid(col)	3da4ec11-3568-cfb4-92aa-b42e99eb957f
BIN_TO_UUID(col)	11eca43d-6835-b4cf-92aa-b42e99eb957f
BIN_TO_UUID(col, true)	6835b4cf-a43d-11ec-92aa-b42e99eb957f

Answer 1

If you're creating and storing them with UUID_TO_BIN(UUID(), true), then you will need to read them back with BIN_TO_UUID(columnName, true).

MySqlDataReader.GetGuid in MySQL Connector/NET (i.e., MySql.Data) has no ability to do this. Some options are:

1. Change your SQL to use BIN_TO_UUID(columnName, true) everywhere, remove Old Guids=true from your connection string, and use GetGuid to read the string that is returned.
2. Stop using the true flag when using UUID_TO_BIN to store the GUID (and just use UUID_TO_BIN(UUID())); this will put the bytes in the order that GetGuid expects.
3. Switch to MySqlConnector and use GuidFormat = TimeSwapBinary16 in your connection string.