Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_79 (lightweight VARCHAR, information_model VARCHAR, flexible VARCHAR)

### Question ###
What is the lightweight value with no information model and the flexible value is unknown?

### Accurate SQL ###

SELECT lightweight FROM table_name_79 WHERE information_model = "no" AND flexible = "unknown"