Interview Questions

1) What is the Advantage of Char over Varchar ..?

Char --  a) Fixed size or length.

              b) Static allocation of memory. 

If you say Char(5) 5 bytes of space is allocated for char. Even if you use only 2 bytes remaining 3 bytes will still be there.

              c) It Stores non unicode characters.

Varchar-- 

              a) Variable size or length

              b) Dynamic memory allocation. 

If you say Varchar(5) and store only 2 bytes. The remaining 3 bytes will not be there.

              c) It stores non unicode characters.

As Char is static memory allocation, it is 50% faster than Varchar.

2) What is the difference between NChar and NVarchar ?

NChar -- Same as Char, except that it stores unicode(double byte) characters.

  By unicode we mean that the characters of different languages like german,chineese which takes 2 bytes.                           

There are some languages which takes 2bytes to store a character like German.

NVarchar -- Same as Varchar , except that it stores unicode(double byte) characters.