Doctrine 2 Insists on Keeping an Already Managed Object in ManyToOne Relationships

Question

I have a database table containing partitions. I have another table containing people. As expected, the department contains many people, and the person is in the same department.

When I want to save a new person in the database, I create a Person object and try to set its Department property to an existing one , which is managed by the Entity Manager. However, when I try to save my new Person, I get an exception:

A new object was found through the relationship "Entities \ Person # department", which was not configured to cascade the saved operations for the object: Entities \ Department @ 0000000016abe202000000000d29dd37. To solve this problem issue: either explicitly call EntityManager # persist () for this unknown entity or cascade configuration that saves this association in the mapping, for example, @ManyToOne (.., cascade = {"persist"}).

I don’t quite understand the part of the exception, which says that the department is an “unknown object”, since I extracted it through the Entity manager.

As the exception shows, I inserted the cascade into the yml metadata ( cascade: ["persist"] ). Then my person will be saved, but in the end I get a duplicated department in the department table with a new identifier.

This should be a very common use case. I have included my code and metadata below. What changes should I make?

Metadata:

 Entities\Person type: entity table: people fields: ... departmentId: type: integer unsigned: false nullable: false column: department_id ... manyToOne: department: targetEntity: Entities\Department joinColumn: department_id referenceColumnName: id 

the code:

 $department = $em->getRepository('Department')->findOneBy(array('name' => $departmentName); $person = new Person(); $person->setName('Joe Bloggs'); $person->setDepartment($department); $em->persist($person); $em->flush(); 

Answer 1

The problem was caused by using different instances of the entity manager to get the department first and then save Person.

My object manager is now singleton, so any class requires that the object manager get the same instance.