如何将mysql的数据表转换为oracle类型的数据库表？

CREATE TABLE answer (
  answer_id number(11) NOT NULL AUTO_INCREMENT,
  answer_content varchar2(255) NOT NULL,
  create_time varchar2(255) NOT NULL,
  user_id number(11) NOT NULL,
  user_name varchar2(255) NOT NULL,
  little_url varchar2(255) DEFAULT NULL,
  parent_id number(11) NOT NULL,
  like_num number(11) unsigned zerofill NOT NULL DEFAULT '00000000000',
  PRIMARY KEY (`answer_id`)
) ENGINE=InnoDB AUTO_INCREMENT=62 DEFAULT CHARSET=utf8;

CREATE TABLE `article` (
  `article_id` int(11) NOT NULL AUTO_INCREMENT,
  `create_time` varchar(200) NOT NULL,
  `content` text,
  `comment_num` int(11) NOT NULL,
  `article_title` varchar(255) NOT NULL,
  `user_id` int(12) DEFAULT NULL,
  `summary` varchar(255) DEFAULT NULL,
  `user_name` varchar(255) NOT NULL,
  `status` char(12) CHARACTER SET ascii NOT NULL,
  PRIMARY KEY (`article_id`)
) ENGINE=InnoDB AUTO_INCREMENT=55 DEFAULT CHARSET=utf8;

CREATE TABLE `article_comment` (
  `comment_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `comment_content` text NOT NULL,
  `article_id` int(11) NOT NULL,
  `comment_time` varchar(25) NOT NULL,
  `user_id` int(11) NOT NULL,
  `user_name` varchar(255) NOT NULL,
  PRIMARY KEY (`comment_id`,`article_id`,`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;

CREATE TABLE `question` (
  `question_id` int(11) NOT NULL AUTO_INCREMENT,
  `question_title` text NOT NULL,
  `create_time` varchar(25) NOT NULL,
  `user_id` int(11) NOT NULL,
  `user_name` varchar(255) NOT NULL,
  `answer_num` int(11) DEFAULT '0',
  `little_url` varchar(255) DEFAULT NULL,
  `question_content` text NOT NULL,
  PRIMARY KEY (`question_id`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8;

CREATE TABLE `relationship` (
  `relation_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `ownner_id` int(11) NOT NULL,
  `friend_id` int(11) NOT NULL,
  `friend_name` varchar(255) NOT NULL,
  `status` varchar(255) NOT NULL,
  `hot_percent` int(3) NOT NULL DEFAULT '50',
  PRIMARY KEY (`relation_id`),
  KEY `index_relationship_friendname` (`friend_name`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=35 DEFAULT CHARSET=utf8;

CREATE TABLE `user` (
  `user_name` varchar(30) NOT NULL,
  `user_id` int(11) NOT NULL AUTO_INCREMENT,
  `pass_word` varchar(30) NOT NULL,
  `user_level` int(1) NOT NULL DEFAULT '0',
  `email` varchar(30) DEFAULT NULL,
  `userpicture_url` varchar(100) CHARACTER SET ascii DEFAULT 'UserPhoto/user.jpg',
  `hot_percent` int(5) DEFAULT '0',
  `little_url` varchar(255) DEFAULT 'LittleUserPhoto/littleuser.jpg',
  PRIMARY KEY (`user_id`),
  KEY `Index_user_user_name` (`user_name`) USING HASH
) ENGINE=InnoDB AUTO_INCREMENT=101 DEFAULT CHARSET=utf8;

CREATE TABLE `user` (
  `user_name` varchar(30) NOT NULL,
  `user_id` int(11) NOT NULL AUTO_INCREMENT,
  `pass_word` varchar(30) NOT NULL,
  `user_level` int(1) NOT NULL DEFAULT '0',
  `email` varchar(30) DEFAULT NULL,
  `userpicture_url` varchar(100) CHARACTER SET ascii DEFAULT 'UserPhoto/user.jpg',
  `hot_percent` int(5) DEFAULT '0',
  `little_url` varchar(255) DEFAULT 'LittleUserPhoto/littleuser.jpg',
  PRIMARY KEY (`user_id`),
  KEY `Index_user_user_name` (`user_name`) USING HASH
) ENGINE=InnoDB AUTO_INCREMENT=101 DEFAULT CHARSET=utf8;