Sequences are a way of offering unique IDs for data rows. If you do most of your work with e.g. MySQL, think of sequences as another way of doing AUTO_INCREMENT. It's quite simple, first you request an ID, and then you insert that value in the ID field of the new row you're creating. You can have more than one sequence for all your tables, just be sure that you always use the same sequence for any particular table. To get the value of this unique ID use nextId() , if a sequence doesn't exists, it will be created automaticlly.

Example 21-1. Using a sequence

... $id = $db->nextId('mySequence'); // Use the ID in your INSERT query $res = $db->query("INSERT INTO myTable (id,text) VALUES ($id,'foo')"); ...

Prev	Home	Next
Introduction - Fetch	Up	Introduction - Execute

Who's Online
Guest Users: 4

Free Sample Chapters
	Deliver First Class Web Sites: 101 Essential Checklists Want to learn how to make your web sites usable and accessible? Want to ensure that your sites meet current best practice, without spending hours trawling through incomprehensible specifications and recommendations from dozens of different books, research papers, and web sites? Want to make sure that the sites you build are "right the first time," requiring no costly redevelopments?
More Sample Chapters

PHP General