2008年9月27日 · nvarchar stores Unicode data while varchar stores single-byte character data. Other than storage differences (nvarchar requires twice the storage space as varchar), which you already mentioned, the main reason for preferring nvarchar over varchar would be internationalization (i.e. storing strings in other languages).

nchar and nvarchar can store Unicode characters. char and varchar cannot store Unicode characters. char and nchar are fixed-length which will reserve storage space for number of characters you specify even if you don't use up all that space. varchar and nvarchar are variable-length which will only use up

2009年3月5日 · I would recommend NVARCHAR for any column which will have user-entered data in it which is relatively unconstrained. I would recommend VARCHAR for any column which is a natural key (like a vehicle license plate, SSN, serial number, service tag, order number, airport callsign, etc) which is typically defined and constrained by a standard or ...

2012年9月28日 · varchar(max) + nvarchar(n) won't truncate (for < 2GB) and the result will be typed as nvarchar(max). nvarchar(max) + varchar(n) will first convert the varchar(n) input to nvarchar(n) and then do the concatenation. If the length of the varchar(n) string is greater than 4,000 characters the cast will be to nvarchar(4000) and truncation will occur.

For your application, nvarchar is fine because the database size is small. Saying "always use nvarchar" is a vast oversimplification. If you're not required to store things like Kanji or other crazy characters, use VARCHAR, it'll use a lot less space. My predecessor at my current job designed something using NVARCHAR when it wasn't needed.

2011年6月20日 · You guys are FAST! So, should I cast SqlDbType.NVarChar back to a DbType for my SqlCeParameter? Right now, VS2010 tells me, "Cannot implicitly convert type 'System.Data.SqlDbType' to 'System.Data.DbType'. An exlicit conversion exists (are you misssing a cast?)" If I'm casting, is that cast not available in the DbType enumeration? –

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.

2012年3月18日 · The "n" in nvarchar/nchar allows you to store text using the unicode number set which is large enough to incorporate all characters in all languages (in principle anyway) with a unique number. This itself isn't related to collations. nvarchar/nchar does not use CODE PAGES to encode/decode the meaning of each character code.

A common misconception is to think that with nchar(n) and nvarchar(n), the n defines the number of characters. However, in nchar(n) and nvarchar(n), the n defines the string length in byte-pairs (0-4,000). n never defines numbers of characters that can be stored. This is similar to the definition of char and varchar.

2009年2月16日 · In today's i18n world, nvarchar makes a lot of sense. varchar might make sense for data that is specified not to be unicode (perhaps you have some system fields that are demanded to be ASCII). I'd use nvarchar by default for …