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难道不可以建立多个索引吗?
下面两个建立表
CREATE DATABASE manage;
use manage;
CREATE TABLE dept
(id int(4) NOT NULL AUTO_INCREMENT,
name varchar(20) NOT NULL default ' ',
PRIMARY KEY (id),
KEY (name)
)TYPE=MyISAM;
INSERT INTO dept (name) VALUES ('computer');
INSERT INTO dept (name) VALUES ('history');
CREATE TABLE student
( id int(4) NOT NULL AUTO_INCREMENT,
name varchar(20) NOT NULL DEFAULT ' ',
sex varchar( 8 ) NOT NULL DEFAULT 'male',
age int(4) DEFAULT '0',
dept varchar(20),
PRIMARY KEY id,
KEY (name),
KEY (sex),
KEY (age),
KEY (dept),
FOREIGN KEY (dept) REFERENCES dept(name) ON DELETE CASCADE
)TYPE=MyISAM;
INSERT INTO student (name,sex,age,dept) VALUES ('xxj','male',34,'computer');
INSERT INTO student (name,sex,age,dept) VALUES ('imp','female',25,'history');
为什么第一个正确通过,第二个就不行?
[ 本帖最后由 xxjoyjn 于 2006-5-22 13:16 编辑 ] |
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