Doctrine gives null while trying to access property of property - doctrine

Question

I am using Doctrine with CodeIgniter.
I can't access the category with this usage. $record is not null but $category is null.
$record_data = $this->getRepository('Entity\RecordData')->find($this->params['id']);
$record = $record_data->getRecord();
$category = $record->getCategory();
echo $category->getName();
Last line gives Fatal error: Call to a member function getName() on a non-object.
What am i doing wrong? Can you have a look please. Thanks.
Here is my entity classes.
Entity\RecordData:
<?php
namespace Entity;
/**
* #Entity(repositoryClass="RecordDataRepository")
* #Table(name="record_data")
*/
class RecordData {
/**
* #Id
* #Column(type="integer", nullable=false)
* #GeneratedValue(strategy="AUTO")
*/
protected $ID;
/**
* #ManyToOne(targetEntity="CategoryVariable")
* #JoinColumn(name="CategoryVariableID", referencedColumnName="ID")
*/
protected $CategoryVariable;
/**
* #ManyToOne(targetEntity="Record")
* #JoinColumn(name="RecordID", referencedColumnName="ID")
*/
protected $Record;
/**
* #ManyToOne(targetEntity="SkillLevel")
* #JoinColumn(name="SkillLevelID", referencedColumnName="ID")
*/
protected $SkillLevel = NULL;
/**
* #Column(type="string", length=255, nullable=true)
*/
protected $Value;
/**
* #Column(type="integer", nullable=false)
*/
protected $RecordDataOrder;
/**
* #Column(type="boolean", nullable=false)
*/
protected $Deleted = FALSE;
public function __construct(Record $record, CategoryVariable $category_variable)
{
$this->Record = $record;
$this->CategoryVariable = $category_variable;
}
public function getID()
{
return $this->ID;
}
public function getCategoryVariable()
{
return $this->CategoryVariable;
}
public function getRecord()
{
return $this->Record;
}
public function setSkillLevel($SkillLevel)
{
$this->SkillLevel = $SkillLevel;
}
public function getSkillLevel()
{
return $this->SkillLevel;
}
public function setValue($Value)
{
$this->Value = $Value;
}
public function getValue()
{
return $this->Value;
}
public function setRecordDataOrder($RecordDataOrder)
{
$this->RecordDataOrder = $RecordDataOrder;
}
public function getRecordDataOrder()
{
return $this->RecordDataOrder;
}
public function delete()
{
$this->Deleted = TRUE;
}
}
Entity\Record:
<?php
namespace Entity;
/**
* #Entity(repositoryClass="RecordRepository")
* #Table(name="record")
*/
class Record {
/**
* #Id
* #Column(type="integer", nullable=false)
* #GeneratedValue(strategy="AUTO")
*/
protected $ID;
/**
* #ManyToOne(targetEntity="Category")
* #JoinColumn(name="CategoryID", referencedColumnName="ID")
*/
protected $Category;
/**
* #Column(type="string", length=255, nullable=true)
*/
protected $Name;
/**
* #Column(type="integer", nullable=false)
*/
protected $RecordOrder;
/**
* #Column(type="string", length=255, nullable=true)
*/
protected $Description;
/**
* #Column(type="boolean", nullable=false)
*/
protected $Deleted = FALSE;
public function __construct(Category $category)
{
$this->Category = $category;
}
public function getID()
{
return $this->ID;
}
public function setCategory($Category)
{
$this->Category = $Category;
}
public function getCategory()
{
return $this->Category;
}
public function setName($Name)
{
$this->Name = $Name;
}
public function getName()
{
return $this->Name;
}
public function setRecordOrder($RecordOrder)
{
$this->RecordOrder = $RecordOrder;
}
public function getRecordOrder()
{
return $this->RecordOrder;
}
public function setDescription($Description)
{
$this->Description = $Description;
}
public function getDescription()
{
return $this->Description;
}
public function delete()
{
$this->Deleted = TRUE;
}
}
Entity\Category:
<?php
namespace Entity;
use Doctrine\Common\Collections\ArrayCollection;
/**
* #Entity(repositoryClass="CategoryRepository")
* #Table(name="category")
*/
class Category {
/**
* #Id
* #Column(type="integer", nullable=false)
* #GeneratedValue(strategy="AUTO")
*/
protected $ID;
/**
* #Column(type="string", length=255)
*/
protected $Name;
/**
* #Column(type="string", length=255)
*/
protected $Description;
/**
* #Column(type="integer", nullable=false)
*/
protected $CategoryOrder;
/**
* #Column(type="boolean", nullable=false)
*/
protected $IsMultiple;
/**
* #Column(type="boolean", nullable=false)
*/
protected $Deleted = FALSE;
public function getID()
{
return $this->ID;
}
public function setName($Name)
{
$this->Name = $Name;
}
public function getName()
{
return $this->Name;
}
public function setDescription($Description)
{
$this->Description = $Description;
}
public function getDescription()
{
return $this->Description;
}
public function setCategoryOrder($CategoryOrder)
{
$this->CategoryOrder = $CategoryOrder;
}
public function getCategoryOrder()
{
return $this->CategoryOrder;
}
public function setIsMultiple($IsMultiple)
{
$this->IsMultiple = $IsMultiple;
}
public function getIsMultiple()
{
return $this->IsMultiple;
}
public function delete()
{
$this->Deleted = TRUE;
}
/**
* #var CategoryVariable[]
* #OneToMany(targetEntity="CategoryVariable", mappedBy="Category")
*/
protected $CategoryVariables = NULL;
/**
* #var Record[]
* #OneToMany(targetEntity="Record", mappedBy="Category")
*/
protected $Records = NULL;
public function setCategoryVariable(CategoryVariable $CategoryVariable)
{
$this->CategoryVariables[] = $CategoryVariable;
}
public function getCategoryVariables()
{
return $this->CategoryVariables;
}
public function setRecord(Record $Record)
{
$this->Records[] = $Record;
}
public function getRecords()
{
return $this->Records;
}
public function __construct()
{
$this->CategoryVariables = new ArrayCollection();
$this->Records = new ArrayCollection();
}
}

Answer 1

If your record doesn't have category then the category object that you retrieve it is null. So before echo its category you must to control if category is a real object or null object.
Like this:
$record_data = $this->getRepository('Entity\RecordData')->find($this->params['id']);
$record = $record_data->getRecord();}
$category = $record->getCategory();
echo ($category) ? $category->getName() : "Record doesn't have category";