MySQL 键：主键、外键、键——什么是“KEY”？
查看“mysqldump -d”并看到一个键是 KEY，而不是“PRIMARY KEY”或“FOREIGN KEY”
什么是 KEY？
示例：
CREATE TABLE IF NOT EXISTS `TABLE_001` (
`COL_001` int(256) NOT NULL,
`COL_002` int(256) NOT NULL,
`COL_003` int(256) NOT NULL,
`COL_004` int(256) NOT NULL,
`COL_005` int(256) NOT NULL,
`COL_006` int(256) NOT NULL,
`COL_007` int(256) NOT NULL,
`COL_008` int(256) NOT NULL,
`COL_009` int(256) NOT NULL,
`COL_010` int(256) NOT NULL,
`COL_011` int(256) NOT NULL,
`COL_012` int(256) NOT NULL,
PRIMARY KEY (`COL_001`),
KEY `COL_002` (`COL_002`,`COL_003`),
KEY `COL_012` (`COL_012`),
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
另外，当我创建此表的新版本时，除了将“ENGINE=MyISAM”更改为“ENGINE=InnoDB”之外，将 MyISAM 更改为 InnoDB 是否还需要进行任何其他更改？
Looking at a "mysqldump -d" and see a key that is KEY, not "PRIMARY KEY" or "FOREIGN KEY"
What is KEY?
Example:
CREATE TABLE IF NOT EXISTS `TABLE_001` (
`COL_001` int(256) NOT NULL,
`COL_002` int(256) NOT NULL,
`COL_003` int(256) NOT NULL,
`COL_004` int(256) NOT NULL,
`COL_005` int(256) NOT NULL,
`COL_006` int(256) NOT NULL,
`COL_007` int(256) NOT NULL,
`COL_008` int(256) NOT NULL,
`COL_009` int(256) NOT NULL,
`COL_010` int(256) NOT NULL,
`COL_011` int(256) NOT NULL,
`COL_012` int(256) NOT NULL,
PRIMARY KEY (`COL_001`),
KEY `COL_002` (`COL_002`,`COL_003`),
KEY `COL_012` (`COL_012`),
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
Also, when I'm create a new version of this table, will changing MyISAM to InnoDB require any additional changes besides "ENGINE=MyISAM" to "ENGINE=InnoDB"?
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KEY是索引声明的替代语法。 CREATE TABLE 语句包括在 COL_002 上创建两个索引和 COL_012 分别。不，这应该没问题，但要注意，您不能在使用 Innodb 引擎的表上使用 MySQL 的本机全文搜索 (FTS)——它们必须是 MyISAM，然后才能对其中的列进行全文索引。
KEYis alternative syntax for index declaration. The CREATE TABLE statement includes creating two indexes, on COL_002 and COL_012 separately.No, that should be fine but be aware that you can't use MySQL's native Full Text Search (FTS) on tables using the Innodb engine -- they have to be MyISAM before you can full text index columns in them.
来自 CREATE TABLE 语法的 MySQL 手册：
From MySQL manual for CREATE TABLE syntax: