From http://dev.mysql.com/doc/refman/5.6/en/innodb-restrictions.html Cascaded foreign key actions do not activate triggers In other words, you cannot use the trigger with cascaded deleting. Also see related bugs: MySQL: https://bugs.mysql.com/bug.php?id=11472 MariaDB: https://jira.mariadb.org/browse/MDEV-19402
In SQL Server Management Studio, go to Options / SQL Server Object Explorer / Scripting, and enable ‘Generate script for dependent objects’. Then right click the table, script > drop to > new query window and it will generate it for you.
I’ll preface this by saying that I rarely delete rows period. Generally most data you want to keep. You simply mark it as deleted so it won’t be shown to users (ie to them it appears deleted). Of course it depends on the data and for some things (eg shopping cart contents) actually deleting the … Read more
Combining your advice and a script I found online, I made a procedure that will produce SQL you can run to perform a cascaded delete regardless of ON DELETE CASCADE. It was probably a big waste of time, but I had a good time writing it. An advantage of doing it this way is, you … Read more
In the Doctrine2 documentation “9.6. Transitive persistence / Cascade Operations” there are few examples of how you should configure your entities so that when you persist $article, the $topic would be also persisted. In your case I’d suggest this annotation for Topic entity: /** * @OneToMany(targetEntity=”Article”, mappedBy=”topic”, cascade={“persist”, “remove”}) */ private $articles; The drawback of … Read more
A foreign key with a cascade delete means that if a record in the parent table is deleted, then the corresponding records in the child table will automatically be deleted. This is called a cascade delete. You are saying in a opposite way, this is not that when you delete from child table then records … Read more
Here’s what you’d include in your components table. CREATE TABLE `components` ( `id` int(10) unsigned NOT NULL auto_increment, `typeId` int(10) unsigned NOT NULL, `moreInfo` VARCHAR(32), — etc PRIMARY KEY (`id`), KEY `type` (`typeId`) CONSTRAINT `myForeignKey` FOREIGN KEY (`typeId`) REFERENCES `types` (`id`) ON DELETE CASCADE ON UPDATE CASCADE ) Just remember that you need to use … Read more
In case of many-to-many relation through intermediary table; “Cascade” says whether a record will be created/updated in the child table. Whereas “Inverse” says whether a record will be created/updated in the intermediary table e.g. Assume below scenario 1 student can have multiple phones. So Student class has property for Set of phones. Also 1 Phone … Read more
ON DELETE CASCADE is fine, but only when the dependent rows are really a logical extension of the row being deleted. For example, it’s OK for DELETE ORDERS to delete the associated ORDER_LINES because clearly you want to delete this order, which consists of a header and some lines. On the other hand, DELETE CUSTOMER … Read more
This is my conclusion of looking into it: The cascade option does not affect the database column constraints, and I believe is used by TypeORM only in evaluating how to save entity relations to the database. We can define entities like this: @Entity() class Book extends BaseEntity { @ManyToOne(() => Author, (author) => author.books, { … Read more