...

• table replace was renamed to entry_replacement - by accident, we have used reserved word

Refined schema (step 8)

Experiment database

• There is a new table: variable_type - it describes possible types of the variables
• Inside variable table, there is no longer variable_type column. Instead there is a foreign key (variable_type_id) that points at variable_type.id
• There is a new table: request_status - it describes possible statues of the request
• Inside request table there is no longer status column - instead there is a foreign key (request_status_id) that points at request_status.id

Image Added