Bite,byte,k,m,g and so are storage units, an English account for a few how much space, a number of space, how much space a Chinese character occupies

Q: Bite,byte,k,m,g and so are storage units, an English account for a few how much space, a number of space, how much space a Chinese character occupies. The database in a table a field B length varcha2 (20) What that means, is how much space is allocated to the field.

For:

1) Bite,byte,k,m,g, etc. are all storage units. 1byte=8bite;1k=1024byte.

2) Any one character, as long as it exists on the computer, is to occupy space.

3) The coding rules are different, the bytes accounted for are different, such as GBK encoding, the Chinese characters accounted for 2 bytes is byte;utf-8 encoded, Chinese characters accounted for 3 bytes.

5) The length of a field in the database Varcha2 (20) What it means, is how much space is allocated to the field. A Table a field B length Varcha2 (20) in an Oracle database represents 20 bytes, which means that if the database is GBK encoded, 10 characters can be stored, if utf-8 The code can save 6.666666 characters or less than 7 Chinese characters.