[orm-devel] How to handle multi language?

[Diedrich Vorberg]

Hi Werner!

> My application supports multiple languages (en, de, fr), my current  
> implementation works but I think there is "space for improvement"  
> and I am looking for some hints/suggestions on how to do this.

> Thanks in advance for any ideas and/or hints.
I've got an idea I used for a web application, It's not ideal,  
though. I used one column per table per language like this:

    CREATE TABLE something
    (
        title_de TEXT,
        description_de TEXT,
        title_en TEXT,
        description_en TEXT
    );

I'm using Livinglogic's XIST XML handling library to create XHTML  
output which represents the XHTML DOM tree using Python classes. I  
inserted the relevant data into the dom tree with the HTML attribute  
lang="" set to the correct language. Just previous to delivery I have  
a little routine walk the DOM tree an delete all entries that do not  
fit the user's language.

If you are writing a GUI application you might want to create the  
model-Module (the one with all the dbclasses in) on startup depending  
on the user's language settings. Than you could mangle the columns  
dicts according to the locale. Like this (just a code-sketch)

    from orm.dbclass import dbclass
    from orm.columns import *
    from orm.firebird.columns import *

    class something(dbclass):
       pass

    something_columns = ( ("title", text, "title_%s"),
                          ("description", text, "description_%s"), )

    class someting_else(dbclass):
        pass

    something_columns = ( ("blah", text, "blah_%s"),
                          ("blub", text, "blub_%s"), )

    # figure out my locale, determine language abriviation, store it  
in lang variable

    for class_name in ("something", "something_else"):
       dbclass = locals()[class_name]
       column_tuples = locals()[class_name]

       columns_dict = {}
       for attribute_name, column_class, sql_column_name in  
column_tuples:
          columns_dict[attribute_name] = column_class 
(column_name="sql_column_name" % lang)

       dbclass.columns = columns_dict

    # now you can normaly instantiate something and something_else


There is another idea I had: a dict_relationship that would let you  
access different columns in a dbclass like a dict as in

    dbobj.attribute[lang]

which maps to SQL column dbobj's attribute_"lang"-column.


Diedrich

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