Re: [Firebird-devel] Adding NOT NULL fields with DEFAULT

[Vlad K. <hv...@us...>]

> Ann W. Harrison wrote:
>> 
>> Here's the problem I see, and it may exist already.
>> 
>> Create a table, which creates format 1 for that table.
>> Store a bunch of records.
>> 
>> Add a NOT NULL field with a default value of 'ABC',
>> which creates format 2 for the table.  The new format
>> includes the default value.
>> 
>> Now if you read records for that table, the new field's
>> value is 'ABC'.
>> 
> That's ok.
> 
>> Now alter the table, changing the default value to '123',
>> creating a new format 3 which includes the new default
>> for that field.
>> 
>> Read the same records again and the value is probably going
>> to be '123'.
>> 
> If the record format is 2, it should return 'ABC'. If the record is updated and written in the 
> format 3, 'ABC' should be written to the field so it doesn't catch the format 3 value when 
> reading it.

    What if record still stored in format 1 ?

Regards,
Vlad