这是来自教程查询我读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)
)
是什么INDEX name (lastName, firstName)
功能?
如果我的问题不清楚,请告诉我。
谢谢
GusDe
这是一个复合索引(索引表2的列)。你可以在这里阅读更多:http://stackoverflow.com/questions/1823685/when-should-i-use-a-composite-index – Galz