Opens an existing BLOB. The BLOB must be initialized by gda_connection_create_blob or obtained from a GdaValue.
see GdaBlobMode.
0 if everything's ok. In case of error, -1 is returned and the provider should have added an error to the connection.
See Implementation
Opens an existing BLOB. The BLOB must be initialized by gda_connection_create_blob or obtained from a GdaValue.