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 spaces for the characters you store.
Also asked, which is better to use varchar or Nvarchar?
If your database will not be storing multilingual data you should use the varchar datatype instead. The reason for this is that nvarchar takes twice as much space as varchar. Basically you need to decide based on what support and extensibility yoy may provide today and tomorrow.
Likewise, what is a Nvarchar data type?
The NVARCHAR data type stores strings of varying lengths. The string can include digits, symbols, and both single-byte and (in some locales) multibyte characters. The main difference between VARCHAR and NVARCHAR data types is the collation order.
What does Nvarchar stand for?
NVarchar – the 'N' in varchar means uNicode. The column can store any Unicode data. The column is a varchar that supports two-byte characters. The most common use for this sort of thing is to store character data that is a mixture of English and non-English symbols.
Why char is faster than varchar?
CHAR is also better than VARCHAR for data that's changed frequently, because a fixed-length row is not prone to fragmentation. The Memory storage engine uses fixed-size rows, so it has to allocate the maximum possible space for each value even when it's a variable-length field.