mirror of
https://github.com/EiffelSoftware/eiffel-org.git
synced 2025-12-06 14:52:03 +01:00
Author:halw
Date:2008-12-07T17:38:05.000000Z git-svn-id: https://svn.eiffel.com/eiffel-org/trunk@127 abb3cda0-5349-4a8f-a601-0c33ac3a8c38
This commit is contained in:
@@ -19,6 +19,7 @@
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* Fixed missing detection of VREG and VRFT errors for labels of a named tuples which is used as an actual generic parameter of a type (fixes eweasel test#tuple012 and test#tuple013), thus some of your code might be broken since the compiler failed to check this before.
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* Fixed eweasel test#valid222 where compiler properly detects VDRS-4 errors when you redefine a repeatedly inherited routine in at least one but not all branches, but fail to provide a local definition.
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* Now a formal generic parameter only conforms to a formal generic parameter, that is to say assignment to a formal generic parameter where the source is of type NONE (i.e <eiffel>Void</eiffel>) will now be rejected by the compiler.
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* Dropped support for older Microsoft C/C++ compilers on Windows platforms. We only support VS 2005 or greater.
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==Bug fixes==
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@@ -8,19 +8,23 @@ Use the [[ref:/libraries/store/reference/db_change_flatshort|DB_CHANGE]] class
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[[ref:/libraries/store/reference/db_change_flatshort|DB_CHANGE]] allows you to modify the database data using the SQL language:
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* Prepare your SQL query and use modify:
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<code>
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modification: DB_CHANGE
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-- Modification tool.
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...
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create modification.make
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modification.modify ("Update CONTACTS set Firstname = ' John'")
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modification: DB_CHANGE
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-- Modification tool.
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...
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create modification.make
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modification.modify ("Update CONTACTS set Firstname = ' John'")
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</code>
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* Commit your changes with your session control:
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<code>
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session_control: DB_CONTROL
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-- Session control.
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...
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session_control.commit
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session_control: DB_CONTROL
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-- Session control.
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...
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session_control.commit
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</code>
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{{tip|It is always better to check the database status for errors before committing changes. }}
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@@ -8,11 +8,14 @@ Use the [[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]]
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[[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] enables your application to get database content using SQL 'select' queries:
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* You can carry out 'select' queries in an intuitive way using directly the SQL language:
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<code>
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selection: DB_SELECTION
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...
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create selection.make
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selection.set_query ("select * from CONTACTS where firstname = 'John'")
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selection.execute
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selection: DB_SELECTION
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-- Selection tool
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...
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create selection.make
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selection.set_query ("select * from CONTACTS where firstname = 'John'")
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selection.execute
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</code>
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{{tip|Always check the database status for errors after your 'select' query. }}
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@@ -15,31 +15,36 @@ To use DB_RESULT, process in 2 steps:
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[[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] class provides different ways to customize result loading:
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* You want to access an '''unique''' row: [[ref:/libraries/store/reference/db_result_flatshort|DB_RESULT]] object is accessible via cursor:
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<code>
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selection: DB_SELECTION
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my_result: DB_RESULT
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...
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selection.query ("...")
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if selection.is_ok then
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selection.load_result
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my_result := selection.cursor
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end
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selection: DB_SELECTION
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my_result: DB_RESULT
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...
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selection.query ("...")
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if selection.is_ok then
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selection.load_result
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my_result := selection.cursor
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end
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</code>
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* You want to load a '''complete list''' of rows: [[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] can store [[ref:/libraries/store/reference/db_result_flatshort|DB_RESULT]] objects in a list. To do this, you have mainly to provide a LIST object to DB_SELECTION with set_container:
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<code>
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selection: DB_SELECTION
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container: ARRAYED_LIST [DB_RESULT]
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create container.make (Max_results)
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...
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selection.set_container (container)
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...
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from
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container.start
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until
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container.after
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loop
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...
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end
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selection: DB_SELECTION
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container: ARRAYED_LIST [DB_RESULT]
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...
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create container.make (Max_results)
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...
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selection.set_container (container)
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...
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from
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container.start
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until
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container.after
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loop
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...
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end
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</code>
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{{tip|Provide [[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] with the LIST structure convenient for what you need to do with the results. }}
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@@ -47,34 +52,40 @@ To use DB_RESULT, process in 2 steps:
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* You want to '''select part''' of the result set: you can set an action in [[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] that will be executed each time a row is loaded. This action can for instance manipulate current row and define a stop condition.
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** You need to define a descendant of class ACTION and set it to [[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] :
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<code>
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class
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MY_ACTION
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inherit
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ACTION
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redefine
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execute, found
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end
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class
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MY_ACTION
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inherit
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ACTION
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redefine
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execute, found
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end
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...
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execute
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do
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i := i + 1
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end
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...
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found: BOOLEAN
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do
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Result := i >= Max_result
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end
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execute
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do
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i := i + 1
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end
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...
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found: BOOLEAN
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do
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Result := i >= Max_result
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end
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</code>
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** Then set action to [[ref:/libraries/store/reference/db_selection_flatshort|DB_SELECTION]] :
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<code>
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selection: DB_SELECTION
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action: MY_ACTION
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...
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selection.set_action (action)
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selection.query ("...")
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if selection.is_ok then
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selection.load_result
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end
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selection: DB_SELECTION
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action: MY_ACTION
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...
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selection.set_action (action)
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selection.query ("...")
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if selection.is_ok then
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selection.load_result
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end
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</code>
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@@ -83,14 +94,16 @@ To use DB_RESULT, process in 2 steps:
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A DB_RESULT object merely carries data retrieved from the database. You have to convert it to a DB_TUPLE to access data within the retrieved row conveniently, i.e. mostly the column values:
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<code>
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selection: DB_SELECTION
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tuple: DB_TUPLE
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...
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create tuple
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tuple.copy (selection.cursor)
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if tuple.count >= 2 and then tuple.column_name (2).is_equal ("Firstname") then
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io.putstring (tuple.item (2).out)
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end
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selection: DB_SELECTION
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tuple: DB_TUPLE
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...
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create tuple
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tuple.copy (selection.cursor)
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if tuple.count >= 2 and then tuple.column_name (2).is_equal ("Firstname") then
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io.putstring (tuple.item (2).out)
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end
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</code>
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