explain_command

explain_command 
      ::= 
      "explain" "plan" 
      [ "set" "statement_id" "=" quoted_string ] 
      [ "into" [ schema_name "." ] table_name [ "@" link_name ] ] 
      "for" 
      ( select_command 
      | insert_command 
      | update_command 
      | delete_command ) 

This rule is called by

to_define_data