I'm just newbie in mysql.
I want to declare my table something like this,
CREATE TABLE `test` (
`NO` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`ID` char(50) CHARACTER SET utf8 NOT NULL ,
`FIRST_NAME` char(50)CHARACTER SET utf8 NOT NULL,
`LAST_NAME` smallint(50)char(50)CHARACTER SET utf8 NOT NULL,
PRIMARY KEY (`NO`),
)
I read in mysql about char and varchar that
The length of a CHAR column is fixed to the length that you declare when you create the table.
My question is that if I use unicode char(50) for chinese, japanese, korean or other unicode characters, would these columns use too much storage in database and can affect the performance?
For english characters, it only can accept up to 50 characters if I declare my table like this?
Is there any better way or is it good to use char(100) for unicode?
Correct me if I'm wrong.
According to the MySQL manual, the number of bytes required by a CHAR(M) column is M x w, where w is "the number of bytes required for the maximum-length character in the character set". This clearly suggests that a CHAR(50) column will store 50 characters, not 50 bytes. If your characters happen to be Chinese, etc., it will still store up to 50 of them. Note that a VARCHAR(50) will also store up to 50 characters, but will (if one ignores the 1-2 byte overhead that comes with a VARCHAR column) take up less storage than a CHAR(50) column when there are fewer than 50 characters stored.
EDIT This applies only if you are using MySQL 5.5 or later. Earlier versions interpreted the length of character and text fields as bytes, not characters.