這是來自教程查詢我讀MySQL的:索引名(姓氏,名字)
CREATE TABLE Employee (
id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
departmentId TINYINT UNSIGNED NOT NULL
COMMENT "CONSTRAINT FOREIGN KEY (departmentId) REFERENCES Department(id)",
firstName VARCHAR(20) NOT NULL,
lastName VARCHAR(40) NOT NULL,
email VARCHAR(60) NOT NULL,
ext SMALLINT UNSIGNED NULL,
hireDate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
leaveDate DATETIME NULL,
INDEX name (lastName, firstName),
INDEX (departmentId)
)
是什麼INDEX name (lastName, firstName)
功能?
如果我的問題不清楚,請告訴我。
謝謝
GusDe
這是一個複合索引(索引表2的列)。你可以在這裏閱讀更多:http://stackoverflow.com/questions/1823685/when-should-i-use-a-composite-index – Galz