I would like to make use of the component "TDBAdvRichEditor"

The datasource points to TClientDataset field, again pointing to a column in a MS SQL Server database.

What datatype shall I define in the SQL database table so it can be compatible with the editor?

If I use the build-in "TDBRichEdit" included in Delphi, I define the datatype as "ntext", and it apparently works. But ntext datatype is incompatible with TDBAdvRichEditor (exception upon opening the dataset: "Invalid stream format")


TDBAdvRichEditor persists natively in a binary format, so you'd need to use a binary blob field. If you want to persist in RTF format, use TAdvRichEditor with TDBAdvRichEditorRTFIO for databinding

How can I configurate the charset of my RTF content?

At this moment this is hardcoded to the standard ANSI CP1252

Is there any solution to display my text correct. 

Words containing ä,ü ö, ß and so on. 

I cannot see an issue with these characters.
Do you have more details how to reproduce this?

I use the ADVRichEditor componente with the TDBAdvRichEditorRTFIO for save & load the Binary Blobfield from my Firebird Database. When I use a word like "Grüße". The Component display this text after save & load it from the Database. 'Gr??e'

Are you sure this is a binary blob field? When you use a binary blob field, you don't need RTF btw, you can use TDBAdvRichEditor.
I have especially retested the functionality of TDBAdvRichEditorRTFIO but could not see an issue here. Perhaps you can separately try TAdvRichEditorRTFIO and save & load from file (and test the file with another editor like WordPad). If this works, the issue must be with the DB field.