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POMulti valued attributes in a table
 

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    <p>I have designed a send message system in which users can send a message to more than one person at a time. so the recipient attribute of a message is multi valued. so i designed an other table called message_recipients. </p> <p>Here are my tables: </p> <pre><code>create table `message`( `message_id` INT(11) NOT NULL primary key auto_increment, `sender` VARCHAR(32) NOT NULL, `topic` VARCHAR(100) NOT NULL, `content` TEXT NOT NULL, `message_date` TIMESTAMP NOT NULL , `readed` VARCHAR(1) NOT NULL DEFAULT 0, `deleted_by_sender` VARCHAR(1) NOT NULL DEFAULT 0, `deleted_by_recipient` VARCHAR(1) NOT NULL DEFAULT 0, FOREIGN KEY(sender) REFERENCES users(user_name) )ENGINE=InnoDB DEFAULT CHARSET=utf8; create table `message_recipients`( `message_id` INT NOT NULL , `recipient` VARCHAR(32) NOT NULL , PRIMARY KEY(message_id,recipient), FOREIGN KEY(message_id) REFERENCES message(message_id) on delete cascade, FOREIGN KEY(recipient) REFERENCES users(user_name) )ENGINE=InnoDB default charset=utf8; </code></pre> <p>When i insert a message in <code>message</code> table i need to get its <code>message_id</code> and insert it with recipient or recipients into <code>message_recipients</code> table. </p> <p>Here is my script: </p> <pre><code>insert into `message`(`sender`,`topic`,`content`) values('me','need help','how to get last inserted row'); select message_id from `message` order by `message_id` desc limit 0,1; </code></pre> <p>When i got the <code>message_id</code>, i can now insert it into <code>message_recipients</code> with some users as recipient, and now question is that; is there any better or more optimized way?</p>
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    1. USnaazanin
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    1. CODon't use `varchar` for a flag field. Use `bit` or `tinyint` depending on your version. You may also want to use an `unsigned` id column
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