Re: varchar and nvarchar, which one to use???

From: Tim S (stahta01_at_juno.com)
Date: 12/25/04 

Date: Fri, 24 Dec 2004 20:31:10 -0500

Example of Dynamic SQL are in NVARCHAR because sp_executesql examples in BOL
use NVARCHAR and the statement sometimes/always gives errors if nvarchar are
not used.

Tim S

"Andrew J. Kelly" <sqlmvpnooospam@shadhawk.com> wrote in message
news:%23xdEbvg6EHA.2012@TK2MSFTNGP15.phx.gbl...
> Steve,
>
> It all depends on what you need to store in that datatype, Unicode or
> Non-unicode data. If you will only deal with the normal ascii characters
> then it is unlikely you will need an NVARCHAR. If you deal with other
> languages and must store a character that requires two bytes to store
> properly then you need to use it. I suggest you read up on on Unicode in
> BooksOnLine to get a better idea of what that is all about. But the
> bottom line is it depends on your business and if you need to characters
> outside of the normal ascii range of 0-255. Using them when you don't
> need that capability can lead to a lot of wasted space in the tables and
> indexes.
>
> --
> Andrew J. Kelly SQL MVP
>
>
> "=== Steve L ===" <steve.lin@powells.com> wrote in message
> news:1103927994.413455.11480@c13g2000cwb.googlegroups.com...
> i'm reading the section of an article at this site
> <<< http://www.sommarskog.se/dyn-search.html>>>
>
> and i was confused the correct use of varchar and nvarchar.
> I've been using varchar in the past, but i noticed all the code samples
> use
> something like this:
>
> DECLARE @sql nvarchar(4000)
> SELECT @sql = 'SELECT * FROM orders'
>
> what's the best practice using these data types?
> for a business like amazon.com as an example, what should be used in
> the database and in the stored procedures? varchar or nvarchar?
>
> can someone educate me on this in a more straight foward fashion?
> thank you!
>
> steve
>
> === excerpt from article ====
> The Northwind database consistently uses the nvarchar data type, but
> I've failed to handle this in my procedure. The data in Northwind
> appears to be restricted to the characters in Windows Latin-1, which
> covers languages such as English, Spanish, French and German, so if you
> have a system collation based on this character set, you would never
> get any incorrect response from search_orders_2. However, a Russian
> user trying:
> EXEC search_orders_2 @city = N'Bräcke'
> would not get the orders from Folk och Fä HB in Bräcke, because
> Bräcke would be converted to varchar as Bracke. This is how my
> procedure should have read: (lines 70-71)
> SELECT @sql2 = @sql2 + N' AND c.City = N' +
> quotename(@city, '''')
> And that N which starts an nvarchar literal, should appear with all
> nvarchar parameters. (The N stands for National, and is taken from the
> ANSI standard SQL-92.)
> So why did I not give you the proper code? Well, I figured that many
> readers would take the code as a template for their own code, and I
> don't want you to include that N by routine. Because, if you use a
> nvarchar literal together with an indexed varchar column, the varchar
> column will be converted to nvarchar, and that precludes use of the
> index. Thus, you would get the right result, but performance would be
> poor.
>
>

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