Add Foreign Constraint doubt

[logicslab]

Hi pals,

 

I create 2 tables with name tbl_project and tbl_issue and I plan to give

Foreign key constraint for tbl_issue by giving alter table command as

"ALTER TABLE `testdrive`.`tbl_issue` ADD CONSTRAINT `FK_issue_project` FOREIGN KEY

 

(`project_id`) REFERENCES `tbl_project`(`id`) ON DELETE CASCADE ON UPDATE RESTRICT"

 

It's successfully executed and when I check the table tbl_issue I found the

Alter table command as "ALTER TABLE `tbl_issue`

  ADD CONSTRAINT `FK_issue_project` FOREIGN KEY (`project_id`) REFERENCES `tbl_project` (`id`) ON DELETE CASCADE;"

 

there missing the "UPDATE RESTRICT" , I feel wonder why this like that ? Do you any one

can explain why this ? If you have idea PLS EXPLAIN

 

THANKS

ANES

[mikosiko]

RESTRICT is the default option for ON DELETE and ON UPDATE, therefore they are not included as part of the table description.

[logicslab]

Thanks Mikosiko for your clear reply .... Do you can suggest a good book for advanced mySql ideas?

 

thanks

Anes