Comparison of string types in the database

There are several types of strings defined in the database: Char, varchar, and nvarchar. The three types are different.

CHAR:

The length of the char type is fixed and the maximum length is 2000 characters. When a field is assigned a value, if the length of the string is smaller than the defined char type, the system automatically fills in the null value. When the value is exceeded, the value is truncated.

Varchar:

Compared with Char, varchar is longer, and its storage space varies according to your string length.

Nvarchar:

Nvarchar is a unicode variable-length type. The main difference between nvarchar and varchar is that it can store more characters in the same length. Unicode encoding uses two bytes to store any character. For example, varchar (3) and nvarchar (3) can store three characters (1.5 Chinese characters ), the latter can store three Chinese characters, which is the difference.