Copying missing translatable data when Primary language is changed

There are 2 types of columns in database tables, that In-Portal uses:

• columns, that have different value on each language (e.g. l1_Name, l2_Name, l3_Name, l1_Description, etc.);
• columns, that have same value on each language (Status, FieldName, Type).

In case, when language-dependent column doesn't have value on given language, then value from primary language is displayed. All works fine, until primary language is changed.

Best way to solve this is to copy data language-dependent data from old primary language columns into new primary language columns.

I think, that kMultiLanguageHelper is perfectly suited for this task, since it already keeps track of all language-dependent columns through all database. For each language-dependent column will issue database query that will copy only missing data, so any entered data on new primary language will be preserved.

Code described above should on primary language change (Set Primary button on toolbar or primary checkbox on language editing).