Does ALTER COLUMN effect the data?

I just want to change the length of 2 fields. They're CHAR and NVARCHAR type. I want to change the length from 50 to 75.

Will doing this effect the data? Will it delete the data in those columns? I just want to make sure before I do anything. The table contains about 2.5 million rows, so I don't want to mess anything up. I'm aware that the script may take a while to run and finish, but I'm only concerned about data integrity.

Here is my example script syntax to show what I'm planning to do:

Code Snippet

alter table credit alter column writeoffreason char(75) not null;

Does it matter what type of data is in the columns? For now, it's only CHAR and NVARCHAR.

I also read somewhere that you can increase length but cannot decrease without repercussions?

Thanks!

It will not delete, but SS has to allocate space in order to accomodate the CHAR one, because it has to pad with spaces to the right. This statement will not only affect metadata, it will affect actual space allocation. Check table fragmentation after it has finished.

AMB

|||thanks for the confirmation, i had thought so that the data integrity would remain intact.