varchar or nvarchar

Question

I am storing first name and last name with up to 30 characters each. Which is better varchar or nvarchar.

I have read that nvarchar

Answer 1

Basically, nvarchar means you can handle lots of alphabets, not just regular English. Technically, it means unicode support, not just ANSI. This means double-width characters or approximately twice the space. These days disk space is so cheap you might as well use nvarchar from the beginning rather than go through the pain of having to change during the life of a product.

If you're certain you'll only ever need to support one language you could stick with varchar, otherwise I'd go with nvarchar.

This has been discussed on SO before here.

EDITED: changed ascii to ANSI as noted in comment.

Answer 2

The nvarchar type is Unicode, so it can handle just about any character that exist in every language on the planet. The characters are stored as UTF-16 or UCS-2 (not sure which, and the differences are subtle), so each character uses two bytes.

The varchar type uses an 8 bit character set, so it's limited to the 255 characters of the character set that you choose for the field. There are different character set that handles different character groups, so it's usually sufficient for text local to a country or a region.

If varchar works for what you want to do, you should use that. It's a bit less data, so it's overall slightly faster. If you need to handle a wide variety of characters, use nvarchar.

Answer 3

First of all, to clarify, nvarchar stores unicode data while varchar stores ANSI (8-bit) data. They function identically but nvarchar takes up twice as much space.

Generally, I prefer storing user names using varchar datatypes unless those names have characters which fall out of the boundary of characters which varchar can store.

It also depends on database collation also. For e.g. you'll not be able to store Russian characters in a varchar field, if your database collation is LATIN_CS_AS. But, if you are working on a local application, which will be used only in Russia, you'd set the database collation to Russian. What this will do is that it will allow you to enter Russian characters in a varchar field, saving some space.

But, now-a-days, most of the applications being developed are international, so you'd yourself have to decide which all users will be signing up, and based on that decide the datatype.