You can specify your own transformations and embed them in a model by creating a transformation list and passing it to DBMS_DATA_MINING.CREATE_MODEL
.
PROCEDURE create_model(
model_name IN VARCHAR2,
mining_function IN VARCHAR2,
data_table_name IN VARCHAR2,
case_id_column_name IN VARCHAR2,
target_column_name IN VARCHAR2 DEFAULT NULL,
settings_table_name IN VARCHAR2 DEFAULT NULL,
data_schema_name IN VARCHAR2 DEFAULT NULL,
settings_schema_name IN VARCHAR2 DEFAULT NULL,
xform_list IN TRANSFORM_LIST DEFAULT NULL);