Doctrine won't save one-to-many relationship - php

Question

I'm being bugged by an issue that seems very very puzzling. FYI - I know and I have read most of the doctrine questions around here, so I know the basics of doctrine and specifying relationships.
Below is how my data model looks (posting relevant sections of code)
class Sample
{
/**
* #ORM\OneToMany(targetEntity="Analysis", mappedBy="sample", cascade={"persist"})
*
protected $analyses
public function addAnalysis(Analysis $analysis)
{
$analyses->setSample($this);
$this->analyses[] = $analyses;
}
}
And Analysis
class Analysis
{
/**
* #ORM\ManyToOne(targetEntity="Sample", inverseBy="analyses", cascade={"persist"})
* #ORM\JoinColumn(name="sample_id", referencedColumnName="id")
*
protected $sample
public function setSample(Sample $sample)
{
$this->sample = $sample;
}
}
So one Sample can have multiple Analysis. While creating a new Analysis however, it is not letting me create one. It is throwing a NOT NULL constraint exception.
Below is the code I tried.
$analysis = new Analysis
$analysis->setUUID("seeebbbfg");
$analysis->setStatus(Analysis::STATUS_DONE);
$sample = $sample->addAnalysis($analysis)
$em->persist($sample);
$em->flush();
I have gone through many links and the doctrine documentation
Doctrine One-To-Many Relationship Won't Save - Integrity Constraint Violation
many-relationship-wont-save-integrity-constraint-violation
Symfony 2 doctrine persist doesn't work after updating Relationship Mapping
Doctrine entities relationship
After going through this Doctrine "A new entity was found through the relationship" error, I tried to persist $analysis before persisting sample, but it gave an 'a new entity was found' error and then this official doctrine documentation
http://doctrine-orm.readthedocs.io/projects/doctrine-orm/en/latest/reference/association-mapping.html
Not sure what I'm missing. Can anyone shed any light on this?
UPDATE 1
[Doctrine\DBAL\Exception\NotNullConstraintViolationException]
An exception occurred while executing
INSERT INTO analysis (id, uuid, type, status, submission_at, sample_id) VALUES (?,?,?,?,?,?) with params [202066, "seeebbbfg", "temp", 2, "2016-5-22 12:16:39", null]
null value in column "sample_id" violates not-null constraint

Answer 1

I think you should add analysisto the Analyses collection before set Sample.
I guess $this->analyses is an ArrayCollection so, use the ArrayCollection::add() method to add a new object.
Please, try this part of code and let me know the result
class Sample
{
/**
* #ORM\OneToMany(targetEntity="Analysis", mappedBy="sample", cascade={"persist"})
*/
protected $analyses
public function __construct()
{
$this->analyses = new ArrayCollection();
}
public function addAnalysis(Analysis $analysis)
{
$this->analyses->add($analysis);
$analysis->setSample($this);
return $this;
}
}

Answer 2

Credreak...
Thanks for this... Doctrine is not very clear how these are constructed.
I actually modified your code to create a instance of "related field" (analyese) as an Array Collection # _construct and then you can populate that Array with the actual Entity by passing it to the addAnalysis() function.
So the order of operations is: (as I understand it)
Construct an instance of Sample w/ an "related field" (analyese) Array
Construct an instance of Analysis and populate the Array
Pass the Analysis Array to the Sample analyese Array
Then flush the sample which will save the Analysis data to the database.
This worked for me.
class Sample
{
/**
* #ORM\OneToMany(targetEntity="Analysis", mappedBy="sample", cascade={"persist"})
*/
protected $analyses
public function __construct()
{
$this->analyses = new ArrayCollection();
}
public function addAnalysis(Analysis $analysis)
{
$this->analyses->add($analysis);
$analyses->setSample($this);
return $this;
}
}