From PHPBB用户手册

# Table: 'phpbb_ranks'
CREATE TABLE phpbb_ranks (
	rank_id mediumint(8) UNSIGNED NOT NULL auto_increment,
	rank_title varchar(255) DEFAULT '' NOT NULL, 等级名称
	rank_min mediumint(8) UNSIGNED DEFAULT '0' NOT NULL, 等级需要的最少贴子数
	rank_special tinyint(1) UNSIGNED DEFAULT '0' NOT NULL, 是否特殊等级, 0表示否
	rank_image varchar(255) DEFAULT '' NOT NULL, 等级图标
	PRIMARY KEY (rank_id)
) CHARACTER SET `utf8` COLLATE `utf8_bin`;