Get a variable ID by looking up its primary key or hash key
Arguments
- conn
An established connection to database using newConnhandler()
- db_table_name
An api key uses to access the database
- table
An api key uses to access the database
- coln_var
An api key uses to access the database
- coln_var_id
An api key uses to access the database
- check_db_table
An api key uses to access the database
