indexing
	status: "See notice at end of class."
	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
	revision: "$Revision: 56675 $"
	access: change, modify, update, insert, delete
	product: eiffelstore
	database: all_bases

class interface
	DB_CHANGE

create 
	make
			-- Create an interface object to change active base.

feature -- Access

	generating_type: STRING_8
			-- Name of current object's generating type
			-- (type of which it is a direct instance)
			-- (from ANY)

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)

	last_parsed_query: STRING_8
			-- Last parsed SQL query
	
feature -- Comparison

	frozen deep_equal (some: ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		ensure -- from ANY
			shallow_implies_deep: standard_equal (some, other) implies Result
			both_or_none_void: (some = Void) implies (Result = (other = Void))
			same_type: (Result and (some /= Void)) implies some.same_type (other)
			symmetric: Result implies deep_equal (other, some)

	frozen equal (some: ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

	is_equal (other: like Current): BOOLEAN
			-- Is `other' attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other.is_equal (Current)
			consistent: standard_is_equal (other) implies Result

	frozen standard_equal (some: ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		ensure -- from ANY
			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

	frozen standard_is_equal (other: like Current): BOOLEAN
			-- Is `other' attached to an object of the same type
			-- as current object, and field-by-field identical to it?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
	
feature {ANY} -- Status report

	is_connected: BOOLEAN
			-- Has connection to the database server succeeded?
			-- (from DB_STATUS_USE)

	is_ok: BOOLEAN
			-- Is last SQL statement ok ?
			-- (from DB_STATUS_USE)
	
feature -- Status report

	conforms_to (other: ANY): BOOLEAN
			-- Does type of current object conform to type
			-- of `other' (as per Eiffel: The Language, chapter 13)?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void

	ht: HASH_TABLE [ANY, STRING_8]
			-- Correspondence table between object references
			-- and mapped keys
			-- (from STRING_HDL)

	ht_order: ARRAYED_LIST [STRING_8]
			-- Keys of ht in order of mapping
			-- (from STRING_HDL)

	is_mapped (key: STRING_8): BOOLEAN
			-- Is `key' mapped to an Eiffel entity?
			-- (from STRING_HDL)
		require -- from STRING_HDL
			ht_not_void: ht /= Void
			keys_exists: key /= Void

	last_query: STRING_8
			-- Last SQL statement used
			-- (from DB_EXPRESSION)

	mapped_value (key: STRING_8): ANY
			-- Value mapped with `key'
			-- (from STRING_HDL)
		require -- from STRING_HDL
			ht_not_void: ht /= Void
			key_exists: key /= Void
			key_mapped: is_mapped (key)
		ensure -- from STRING_HDL
			result_exists: Result /= Void

	same_type (other: ANY): BOOLEAN
			-- Is type of current object identical to type of `other'?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
	
feature {ANY} -- Status setting

	set_trace
			-- Trace queries sent to database server.
			-- (from DB_EXEC_USE)
		ensure -- from DB_EXEC_USE
			trace_status: is_tracing
	
feature -- Status setting

	clear_all
			-- Remove all mapped keys.
			-- (from STRING_HDL)
		require -- from STRING_HDL
			ht_not_void: ht /= Void

	set_map_name (n: ANY; key: STRING_8)
			-- Store item `n' with key `key'.
			-- `n' can be `Void'.
			-- (from STRING_HDL)
		require -- from STRING_HDL
			ht_not_void: ht /= Void
			key_exists: key /= Void
			not_key_in_table: not is_mapped (key)
		ensure -- from STRING_HDL
			ht.count = old ht.count + 1

	set_query (query: STRING_8)
			-- Set last_query with `query'.
			-- (from DB_EXPRESSION)
		require -- from DB_EXPRESSION
			query_not_void: query /= Void
		ensure -- from DB_EXPRESSION
			last_query_changed: last_query = query

	unset_map_name (key: STRING_8)
			-- Remove item associated with key `key'.
			-- (from STRING_HDL)
		require -- from STRING_HDL
			ht_not_void: ht /= Void
			key_exists: key /= Void
			item_exists: is_mapped (key)
		ensure -- from STRING_HDL
			ht.count = old ht.count - 1
	
feature -- Duplication

	copy (other: like Current)
			-- Update current object using fields of object attached
			-- to `other', so as to yield equal objects.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: is_equal (other)

	frozen deep_copy (other: like Current)
			-- Effect equivalent to that of:
			--		copy (`other' . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)

	frozen deep_twin: like Current
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		ensure -- from ANY
			deep_equal: deep_equal (Current, Result)

	frozen standard_copy (other: like Current)
			-- Copy every field of `other' onto corresponding field
			-- of current object.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)

	frozen standard_twin: like Current
			-- New object field-by-field identical to `other'.
			-- Always uses default copying semantics.
			-- (from ANY)
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)

	frozen twin: like Current
			-- New object equal to `Current'
			-- twin calls copy; to change copying/twining semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result.is_equal (Current)
	
feature -- Basic operations

	frozen default: like Current
			-- Default value of object's type
			-- (from ANY)

	frozen default_pointer: POINTER
			-- Default value of type `POINTER'
			-- (Avoid the need to write `p'.default for
			-- some `p' of type `POINTER'.)
			-- (from ANY)

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)

	execute_query
			-- Execute modify with last_query.
		require -- from DB_EXPRESSION
			last_query_not_void: last_query /= Void

	modify (request: STRING_8)
			-- Execute `request' to modify persistent objects.
			-- When using the DBMS layer the request must be
			-- SQL-like compliant.
		require
			connected: is_connected
			request_exists: request /= Void
			is_ok: is_ok
		ensure
			last_query_changed: last_query = request
	
feature -- Output

	io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- Was declared in ANY as synonym of tagged_out.
			-- (from ANY)

	print (some: ANY)
			-- Write terse external representation of `some'
			-- on standard output.
			-- (from ANY)

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- Was declared in ANY as synonym of out.
			-- (from ANY)
	
feature -- Platform

	operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
	
invariant
		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

indexing
	copyright: "Copyright (c) 1984-2006, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
	source: "[
		Eiffel Software
		356 Storke Road, Goleta, CA 93117 USA
		Telephone 805-685-1006, Fax 805-685-6869
		Website http://www.eiffel.com
		Customer support http://support.eiffel.com
	]"

end -- class DB_CHANGE