Wednesday, November 7, 2007


- MySQL has ENUM type, it is used to enforce the data integrity and de-normalize table. Those joins may add unnecessary complexity to your database.

create table reservations (
   reservation_id int unsigned auto increment primary key,
   seat_pref_description enum('Window', 'Aisle')

Should a user place a invalid value to this column, MySQL will block the incorrect entry and place NULL instead.

- CHAR and VARCHAR have maximum length 255 limitation, can followed by keyword BINARY, mean string comparison case sensitive. Longer string is stored as TEXT type or BLOB( for binary data).

- Two (or more) storage engines: INNODB, MYISAM. The default engine can be specified with parameter default-storage-engine in my.ini.
INNODB: support transaction safe, row-level locking and foreign key
MYISAM: faster, and support full-text searching

create table example(field1 int, field2 varchar(30)) engine=MYISAM;

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