deferred class
     DB_EXPRESSION

General
     cluster: eiffelstore.interface

Ancestors
     STRING_HDL

Queries
     is_mapped (key: STRING): BOOLEAN
     last_query: STRING
     mapped_value (key: STRING): ANY

Commands
     clear_all
     execute_query
     set_map_name (n: ANY; key: STRING)
     set_query (query: STRING)
     unset_map_name (key: STRING)