CREATE TABLE `wf_arc` (
`workflow_id` smallint(5) unsigned NOT NULL default '0',
`transition_id` smallint(5) unsigned NOT NULL default '0',
`place_id` smallint(5) unsigned NOT NULL default '0',
`direction` char(3) NOT NULL default '',
`arc_type` varchar(10) NOT NULL default 'SEQ',
`pre_condition` text,
`created_date` datetime NOT NULL default '0000-00-00 00:00:00',
`created_user` varchar(16) default NULL,
`revised_date` datetime default NULL,
`revised_user` varchar(16) default NULL,
PRIMARY KEY (`workflow_id`,`transition_id`,`place_id`,`direction`),
KEY `place_id` (`workflow_id`,`place_id`,`direction`),
KEY `transition_id` (`workflow_id`,`transition_id`,`direction`)
) ENGINE=MyISAM;------------------------------------------------------------------------------------
PRIMARY KEY (`workflow_id`,`transition_id`,`place_id`,`direction`),这句就是说将(`workflow_id`,`transition_id`,`place_id`,`direction`都设置为主键!那下面两行呢?我想请问一下
KEY `place_id` (`workflow_id`,`place_id`,`direction`),
KEY `transition_id` (`workflow_id`,`transition_id`,`direction`)
这两句话是什么意思呢?
还有,一个表建立四个主键的?
这样有什么好处,有什么那位知道呢?
偶来请教各位了……
`workflow_id` smallint(5) unsigned NOT NULL default '0',
`transition_id` smallint(5) unsigned NOT NULL default '0',
`place_id` smallint(5) unsigned NOT NULL default '0',
`direction` char(3) NOT NULL default '',
`arc_type` varchar(10) NOT NULL default 'SEQ',
`pre_condition` text,
`created_date` datetime NOT NULL default '0000-00-00 00:00:00',
`created_user` varchar(16) default NULL,
`revised_date` datetime default NULL,
`revised_user` varchar(16) default NULL,
PRIMARY KEY (`workflow_id`,`transition_id`,`place_id`,`direction`),
KEY `place_id` (`workflow_id`,`place_id`,`direction`),
KEY `transition_id` (`workflow_id`,`transition_id`,`direction`)
) ENGINE=MyISAM;------------------------------------------------------------------------------------
PRIMARY KEY (`workflow_id`,`transition_id`,`place_id`,`direction`),这句就是说将(`workflow_id`,`transition_id`,`place_id`,`direction`都设置为主键!那下面两行呢?我想请问一下
KEY `place_id` (`workflow_id`,`place_id`,`direction`),
KEY `transition_id` (`workflow_id`,`transition_id`,`direction`)
这两句话是什么意思呢?
还有,一个表建立四个主键的?
这样有什么好处,有什么那位知道呢?
偶来请教各位了……
'截至2009-10-23 11:16:05 用户结帖率0.00%
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