LBP is faster (a few times faster) but less accurate. (10-20% less than Haar). If you want to detect faces on an embedded system, LBP is the default choice, because it does its calculations in integers. Haar uses floats for processing, which have poorer support on embedded and mobile processors; as a result, the performance … Read more
The way you have it mapped, the User is the managing side of the relationship, therefore it will be responsible for updating the join table. Change the JoinTable mapping from User to Group, and make the groupList property of User so it has the mappedBy attribute. That will change the group to the managing side … Read more
From MySQL Documentation: https://dev.mysql.com/doc/refman/8.0/en/create-table-foreign-keys.html Some database systems have deferred checks, and NO ACTION is a deferred check. In MySQL, foreign key constraints are checked immediately, so NO ACTION is the same as RESTRICT.
The basic difference between them is: When using the orphanRemoval=true option Doctrine makes the assumption that the entities are privately owned and will NOT be reused by other entities. If you neglect this assumption your entities will get deleted by Doctrine even if you assigned the orphaned entity to another one. Say your User has … Read more
persist & remove You are correct about cascade={“persist”} meaning that persisting entity A, Doctrine will also persist all B entities in the Collection. You are also correct about cascade={“remove”} meaning that removing entity A, Doctrine will also remove all B entities in the Collection. But I doubt you would ever want to use this on … Read more
onDelete=”CASCADE” is managed by the database itself. cascade={“remove”} is managed by doctrine. onDelete=”CASCADE” is faster because the operations are performed on database level instead by doctrine. The removing is performed by the database server and not Doctrine. With cascade={“remove”} doctrine has to manage the entity itself and will perform extra checks to see if it … Read more
Cascade will work when you delete something on table Courses. Any record on table BookCourses that has reference to table Courses will be deleted automatically. But when you try to delete on table BookCourses only the table itself is affected and not on the Courses follow-up question: why do you have CourseID on table Category? … Read more
Summary of what I’ve seen so far: Some people don’t like cascading at all. Cascade Delete Cascade Delete may make sense when the semantics of the relationship can involve an exclusive “is part of” description. For example, an OrderLine record is part of its parent order, and OrderLines will never be shared between multiple orders. … Read more
I’m pretty sure you can’t simply add on delete cascade to an existing foreign key constraint. You have to drop the constraint first, then add the correct version. In standard SQL, I believe the easiest way to do this is to start a transaction, drop the foreign key, add a foreign key with on delete … Read more
orphanRemoval has nothing to do with ON DELETE CASCADE. orphanRemoval is an entirely ORM-specific thing. It marks “child” entity to be removed when it’s no longer referenced from the “parent” entity, e.g. when you remove the child entity from the corresponding collection of the parent entity. ON DELETE CASCADE is a database-specific thing, it deletes … Read more