MySQL目录结构解析与隐含文件管理

五、其他的特色：

CREATE TABLE invoice (

invoice_id int(10) unsigned NOT NULL auto_increment,

invoice_no int(10) unsigned DEFAULT ’0’ NOT NULL,

payee char(40) DEFAULT ’’ NOT NULL,

PRIMARY KEY (invoice_id),

KEY payee (payee)

);

INSERT INTO invoice VALUES (1,100,’Company AB’);

INSERT INTO invoice VALUES (2,101,’Company CD’);

INSERT INTO invoice VALUES (3,102,’Company EF’);

因为 MySQL 没有办法使用记录号，所以我们必须建立主键。

就有了以下的目录结构：

这样，每个列出现在不同的文件行之中，文件树的结构如下：

/mountpoint/database/table/.table

和

/mountpoint/database/table/primary_key/.record

/mnt/mysql/mydata/invoice/.table

/mnt/mysql/mydata/invoice/1/.record

/mnt/mysql/mydata/invoice/1/invoice_id

/mnt/mysql/mydata/invoice/1/invoice_no

/mnt/mysql/mydata/invoice/1/payee

/mnt/mysql/mydata/invoice/2/.record

/mnt/mysql/mydata/invoice/2/invoice_id

/mnt/mysql/mydata/invoice/2/invoice_no

/mnt/mysql/mydata/invoice/2/payee

/mnt/mysql/mydata/invoice/3/.record

/mnt/mysql/mydata/invoice/3/invoice_id

/mnt/mysql/mydata/invoice/3/invoice_no

/mnt/mysql/mydata/invoice/3/payee

这些文件是隐含的，以防重复，主要用来方便地通过文该篇文章件

浏览器来查看。

/mountpoint/database/table/primary_key/.max

或者

/mnt/mysql/mydata/invoice/invoice_id/.max

或者指向

/mountpoint/database/table/field

和

/mnt/mysql/mydata/invoice/3

/mnt/mysql/mydata/.keys/

/mnt/mysql/mydata/.keys/invoice_id/

/mnt/mysql/mydata/.keys/payee/

还有一些隐藏文件提供键类型：

/mnt/mysql/mydata/.keys/invoice_id/.type

/mnt/mysql/mydata/.keys/payee/.type

另外还可以用索引来排序记录，如果读取下面的目录：

PHP 的readdir() 函数就以升序返回数据的符号连接。

/mountpoint/.version

/mountpoint/.last_insert_id

/mountpoint/.uptime

/mountpoint/database/.raid (0/1)

/mountpoint/database/.type (ISAM/MyISAM/HEAP/DBD)

/mountpoint/database/.tables

/mountpoint/database/table/.created

/mountpoint/database/table/.last_updated

/mountpoint/database/table/.last_checked

/mountpoint/database/table/.count