Doctrine 2.1 - Change field (attribute of entity) mapping on the fly - php

Is it safe to change name of database column on the fly in Doctrine's mapping in application's bootstrap in case I will do it for all created entity managers?
<?php
// In "every second" view sort by score2 instead of by score1
if (rand(0, 1) % 2 === 0) {
$entityManager->getMetadataFactory()->getMetadataFor('Advertisement')->fieldMappings['score']['columnName'] = 'score2';
}
Score attribute is used for sorting of displayed entities and I would like to do A/B testing of sorting by different database columns in the easiest way.

Ok so it seems I have solution.
The best way is probably to make own ClassMetadataFactory which is extended from \Doctrine\ORM\Mapping\ClassMetadataFactory and create EntityManagers with this ClassMetadataFactory.
<?php
/**
* Implementation of Doctrine's metadata factory class for A/B testing
*/
class ClassMetadataFactory extends \Doctrine\ORM\Mapping\ClassMetadataFactory
{
/**
* Gets the class metadata descriptor for a class.
*
* #param string $className The name of the class.
* #return Doctrine\ORM\Mapping\ClassMetadata
*/
public function getMetadataFor($className)
{
$metadata = parent::getMetadataFor($className);
if ($className === 'Advertisement' || $className === '\Advertisement') {
$metadata->fieldMappings['score']['columnName'] = 'score2';
$metadata->fieldNames['score'] = 'score2';
$metadata->columnNames['score'] = 'score2';
}
return $metadata;
}
}
Another thing you should be aware of is Doctrine's DQL cache!
This is relative silly example. Next step could be to do configuration of A/B testing and some switch responsible for variant decision, but this is out of topic my question above.

Related

optional multiple oneToMany relation in symfony2

I have entities in Doctrine Symfony2: User, Channel, Video and Comment; user can report one of them. I designed Report entity with these fields:
userId
status
reportTime
description
how can I reference to reported Entity ?? because all reported fields are similar for all entities I want to use just one table for Report and add these fields to Report Entity:
referenceEntityName(a string and may be one of these: User, Channel, Video, Comment)
Channel(ManytoOne relation to Channel entity)
Video(ManytoOne relation to Video entity)
Comment(ManytoOne relation to Comment entity)
User(ManytoOne relation to User entity)
Is this best practice or I should create separate tables for each kind of report ??
Edit:
based on #Alex answer, I improved Report class and add these methods:
setEntity($entity){
if ($obj instanceof Video){
$this->referenceEntityName = 'Video';
$this->setVideo();
}
elseif($obj instanceof Comment){
$this->referenceEntityName == 'Comment'
$this->setComment();
}
//...
}
getEntity(){
if($this->referenceEntityName == 'Video'){
$this->getVideo()
}// ifelse statements for other entities ...
}
I till have 4 relation that just one of them is used for each instance, isn't it a bit messy!?
and again is this best practice or I should do something else?
what if I want to use FormBuilder class, isn't there any problem??
In a simple solution, whereby for example you only had Users (and not Videos, Comments and Channels), the solution would be simple; each User can have many Reports, and each Report must belong to only one User. This is a one-to-many relationship - one User has many Reports. In Symfony 2 and Doctrine, this would be modelled as such:
// src/Acme/DemoBundle/Entity/User.php
// ...
use Doctrine\Common\Collections\ArrayCollection;
class User
{
// ...
/**
* #ORM\OneToMany(targetEntity="Report", mappedBy="user")
*/
protected $reports;
public function __construct()
{
$this->reports = new ArrayCollection();
}
// ...
}
and
// src/Acme/DemoBundle/Entity/Report.php
// ...
class Report
{
// ...
/**
* #ORM\ManyToOne(targetEntity="User", inversedBy="reports")
* #ORM\JoinColumn(name="user_id", referencedColumnName="id")
*/
protected $user;
// ...
}
In this instance, to create a Report and associate it with a User, we would:
// get the User the Report will belong to
$user = $em->getRepository('AcmeDemoBundle:User')->find(1);
// create the Report
$report = new Report();
// add the User to the Report
$report->setUser($user);
// then persist it, etc ...
Note, the setUser() method is available because the console command was run to generate them automatically. This is highly recommended as it created the necessary type hinting for you. For pre Symfony 2.5 installations, the command is:
php app/console doctrine:generate:entities Acme
>= 2.5 installations, the command is:
php bin/console doctrine:generate:entities Acme
Your requirements complicate this simple example somewhat, as Reports can also belong to Comments and Videos etc. For the sake of the example, let's call these things Entities. A bad approach would be to simply add 3 new properties to the Report, one for each of the new Entities, and then add 3 new setter methods for the Entities. This is bad for 2 reasons: a Report will only ever belong to one of the Entities, and therefore 3 of the properties and setter methods will never be used for each Report entity. Secondly, if you add a new Entity to your business model, or remove one, you need to edit your Report entity, and also the database schema.
A better method is to simply have one property and set method in your Report, that can be applied to all of your Entities. So instead of calling setUser, we could call a setEntity, and have it accept any of the 4. With this approach in mind, let's look back at the first example, and take note of the type hinting in the function signature that would have been produced for the setUser method:
public function setUser(Acme\DemoBundle\Entity\User $user)
See that it requires to be of type Acme\DemoBundle\Entity\User. How do we overcome this, and have it accept any of the 4 Entities? The solution is to have all Entities be derived from a parent class. Then make the function type hint at the base class:
public function setUser(Acme\DemoBundle\Entity\Base $entity)
The base class will contain all common elements, notably a 'name', and as array collection of Reports:
// src/Acme/DemoBundle/Entity/Base.php
// ...
use Doctrine\Common\Collections\ArrayCollection;
class Base
{
// ...
/**
* #ORM\Column(name="name", type="text")
*/
protected $name
/**
* #ORM\OneToMany(targetEntity="Report", mappedBy="baseEntity")
*/
protected $reports;
public function __construct()
{
$this->reports = new ArrayCollection();
}
// ...
}
and then for each child, for example a User and a Video:
// src/Acme/DemoBundle/Entity/User.php
// ...
use AcmeDemoBundle\Entity\Base;
class User extends Base
{
/**
* #ORM\Column(name="firstname", type="text")
*/
protected $firstName;
// ...
}
and the Video
// src/Acme/DemoBundle/Entity/Video.php
// ...
use AcmeDemoBundle\Entity\Base;
class Video extends Base
{
/**
* #ORM\Column(name="title", type="text")
*/
protected $title;
// ...
and change our Report Entity:
// src/Acme/DemoBundle/Entity/Report.php
// ...
class Report
{
// ...
/**
* #ORM\ManyToOne(targetEntity="Base", inversedBy="reports")
* #ORM\JoinColumn(name="base_id", referencedColumnName="id")
*/
protected $baseEntity;
// ...
}
Remember to run the doctrine command to generate the setBaseEntity method. When you do, notice that it will now accept any class derived of Base
Then, to put on a Report on a Video for example, we get the Video, create a Report, and add the Video to the Report:
$video = // get the video you want
$report = new Report();
$report->setBaseEntity($video);
To retrieve all Reports belonging to a Comment, we get the Comment, and get the Reports:
$video = // get the video you want
$reports = $video->getReports();
foreach($reports as $report){
$reportText = $report->getText(); // assuming the Report has a `text` field
}
Update:
The inheritance relationship between these Entities can be modelled in the database with Doctrine using Single Table Inheritance:
/**
* #ORM\Entity
* #ORM\Table(name="base_entities")
* #ORM\InheritanceType("SINGLE_TYPE")
* #ORM\Discriminator(name="entity_type", type="string")
* #ORM\DiscriminatorMap({"user" = "User", "comment" = "Comment", "video" = "Video", "channel" = "Channel"})
*/

Zend Framework Model, Active Record pattern alternative

I'm writing some code that allows users to read reports on a site, using AJAX calls to dynamically load only what is requested, instead of the entire 15+MB report.
I'm writing a Model to access all the report data from the database, and I don't want to use the Active Record pattern. I'm following the idea of "A Model HAS a table, instead of IS-A table", since this model will be accessing 5 different tables, and there are some complex MySQL JOIN's between these tables.
What is a good design pattern to follow in Zend Framework for this, examples?
UPDATED on 2012-12-05 # 12:14PM EST
I'm currently working for a Market Research Report company. Without using actual function names, or revealing any meaningful details of the code, here are the basics:
readreportAction() does:
get the report meta data
get the report "table of contents"
readsectionAction() does:
get the report text, only a part of it
get the embedded tabular data
get the figures / images
get the footnotes
format the report text
reportpdfAction() does the exact same thing as readreportAction() and readsectionAction(), except all at one time. I'm trying to conceptualize a way to NOT copy + paste this code / programming logic. A data mapper seems to solve this.
I would recommend the Data Mapper pattern.
Everything you said makes sense and this pattern fits. Your model should not know or care how it is persisted. Instead the mapper does what it suggests - maps your model to your database. One of the things I like about this approach is it encourages people to think about the model in terms of an object, not a relational database table, as often happens with active record patterns and table row gateways.
Your object, unless very simple, typically will not reflect the structure of a database table. This lets you write good objects and then worry about the persistence aspects afterward. Sometimes more manual in that your mapper will need to deal with the complex joins, probably requiring writing some code or SQL, but the end result is it does just what you want and nothing more. No magic or conventions required if you don't want to leverage them.
I've always though these articles do a good job of explaining some of the design patterns that can be used well in ZF: http://survivethedeepend.com/zendframeworkbook/en/1.0/implementing.the.domain.model.entries.and.authors#zfbook.implementing.the.domain.model.entries.and.authors.exploring.the.entry.data.mapper
UPDATE:
Well you mapper might extend from an interface similar to this:
<?php
interface Mapper_Interface
{
/**
* Sets the name of the entity object used by the mapper.
*/
public function setObjectClass($class);
/**
* Sets the name of the list class used by the mapper.
*/
public function setObjectListClass($listClass);
/**
* Get the name of the object class used by the mapper.
*
*/
public function getObjectClass();
/**
* Get the name of the object list class used by the mapper.
*
* #return string
*/
public function getObjectListClass();
/**
* Fetch one row.
*
* #param array $where Criteria for the selection.
* #param array [$order = array()] Optionally the order of results
* #return Object_Abstract
* #throws Mapper_Exception
*/
public function fetchRow($where, $order = array());
/**
* Fetch all records. If there is no underlying change in the persisted data this should
* return a consistant result.
*
* #param string|array|Zend_Db_Table_Select $where OPTIONAL An SQL WHERE clause or Zend_Db_Table_Select object.
* #param string|array $order OPTIONAL An SQL ORDER clause.
* #param int $count OPTIONAL An SQL LIMIT count.
* #param int $offset OPTIONAL An SQL LIMIT offset.
* #return Object_List_Abstract
* #throws Mapper_Exception
*/
public function fetchAll($where = null, $order = null, $count = null, $offset = null);
/**
* Deletes one or more object.
*
* #param array|string $where Criteria for row deletion.
* #return integer $affectedRows
* #throws Mapper_Exception
*/
public function delete($where);
/**
* Saves a record. Either updates or inserts, as required.
*
* #param $object Object_Abstract
* #return integer $lastInsertId
* #throws Mapper_Exception
*/
public function save($object);
}
And you would interact with the mapper like:
$fooObjectMapper = new Foo_Mapper;
$fooObjectList = $fooObjectMapper->fetchAll();
var_dump($fooObjectList->first());
or
$fooObjectMapper = new Foo_Mapper;
$fooObject = $fooObject->fetch(array('id = ?' => 1));
$fooObject->setActive(false);
$fooObjectMapper->save($fooObject);
I usually write a mapper abstract for any 'PDO' enabled databases. One of the attributes of that concrete mapper is then the Zend_Db_Adapter to issue commands against. Makes for a flexible solution, easy to use mock data sources in testing.
First it looks like you need to make a little bit more of a conceptual leap. With the data mapper pattern it helps to think in terms of objects instead of database tables. I found these two articles helpful when I needed to make the leap.
http://phpmaster.com/building-a-domain-model/
http://phpmaster.com/integrating-the-data-mappers/
That being said ZF 1 has some very useful tools for building a data mapper/domain model.
The convention in ZF 1 is for each table you are working with to be accessible through the Zend_Db_Table api. The simplest way I've found is to just use the DbTable resource for each table. You could also use the Zend_Db::factory or new Zend_Db_Table('tableName') or any other method that appeals to you.
This example is based on a mp3 song track.
//in effect this is the database adapter for database table 'track', This is $tableGateway used later.
<?php
class Application_Model_DbTable_Track extends Zend_Db_Table_Abstract
{
//name of database table, required to be set if name of class does not match name of table
protected $_name = 'track';
//optional, column name of primary key
protected $_primary = 'id';
}
there are several ways to attach a table to the Db adapter and the Zend_Db_Table api, I just find this method simple to implement and it makes setting up a mapper simple as well.
The mapper class is the bridge between the data source and your object (domain entity). The mapper interacts with the api for Zend_Db_Table in this example.
A really important point to understand: when using classes that extend Zend_Db_Table_Abstract you have all the basic functionality of the Zend_Db component at your disposal. (find(),fetchall(), fetchRow(), select() ...)
<?php
class Music_Model_Mapper_Track extends Model_Mapper_Abstract
{
//the mapper to access the songs artist object
protected $artistMapper;
//the mapper to access to songs album object
protected $albumMapper;
/**
* accepts instance of Zend_Db_Table_Abstract
*
* #param Zend_Db_Table_Abstract $tableGateway
*/
public function __construct(Zend_Db_Table_Abstract $tableGateway = null)
{
//at this point I tend to hardcode $tablegateway but I don't have to
$tableGateway = new Application_Model_DbTable_Track();
parent::__construct($tableGateway);
//parent sets the $tablegateway variable and provides an abstract requirement
//for createEntity(), which is the point of this class
}
/**
* Creates concrete object of Music_Model_Track
*
* #param object $row
* #return Music_Model_Track
*/
public function createEntity($row)
{
$data = array(
'id' => $row->id,
'filename' => $row->filename,
'format' => $row->format,
'genre' => $row->genre,
'hash' => $row->hash,
'path' => $row->path,
'playtime' => $row->playtime,
'title' => $row->title,
'track_number' => $row->track_number,
'album' => $row->album_id,//foriegn key
'artist' => $row->artist_id//foriegn key
);
//instantiate new entity object
return new Music_Model_Track($data);
}
/**
* findById() is proxy for find() method and returns
* an entity object.
*
* #param type $id
* #return object Model_Entity_Abstract
*/
public function findById($id)
{
//instantiate the Zend_Db_Select object
$select = $this->getGateway()->select();
$select->where('id = ?', $id);
//retrieve one database table row
$row = $this->getGateway()->fetchRow($select);
//create one entity object Music_Model_Track
$entity = $this->createEntity($row);
//return one entity object Music_Model_Track
return $entity;
}
//truncated
}
All that has gone before is for the express purpose of building the following object:
<?php
class Music_Model_Track extends Model_Entity_Abstract
{
/**
* $id, __set, __get and toArray() are implemented in the parent
*/
protected $album;
protected $artist;
protected $filename;
protected $format;
protected $genre;
protected $hash;
protected $path;
protected $playtime;
protected $title;
protected $track_number;
//artist and album mappers
protected $albumMapper = null;
protected $artistMapper = null;
//these are the important accessors/mutators because they convert a foreign key
//in the database table to an entity object.
public function getAlbum()
{
//if the album object is already set, use it.
if(!is_null($this->album) && $this->album instanceof Music_Model_Album) {
return $this->album;
} else {
//else we make a new album object
if(!$this->albumMapper) {
$this->albumMapper = new Music_Model_Mapper_Album();
}
//This is the album object we get from the id in our reference array.
return $this->albumMapper->findById($this->getReferenceId('album'));
}
}
//same as above only with the artist object.
public function getArtist()
{
if(!is_null($this->artist) && $this->artist instanceof Music_Model_Artist) {
return $this->artist;
} else {
if(!$this->artistMapper) {
$this->artistMapper = new Music_Model_Mapper_Artist();
}
return $this->artistMapper->findById($this->getReferenceId('artist'));
}
}
//the setters record the foriegn keys recorded in the table row to an array,
//this allows the album and artist objects to be loaded only when needed.
public function setAlbum($album)
{
$this->setReferenceId('album', $album);
return $this;
}
public function setArtist($artist)
{
$this->setReferenceId('artist', $artist);
return $this;
}
//standard setter and getters truncated...
}
so when using the track object you would get album or artist info like:
//this would be used in a controller most likely.
$mapper = new Music_Model_Mapper_Track();
$track = $mapper->findById('1');
//all of the information contained in the album or artist object is
//available to the track object.
//echo album title, year or artist. This album object also contains the artist object
//so the artist object would be available in two ways.
echo $track->album->title; //or
echo $track->artist->name;
echo $track->album->artist->name;
echo $track->getAlbum()->getArtist()->getName();
So what you really need to decide is how you want to structure your application. What I see as obvious may not be an option you wish to implement. A lot of the answers to your questions depend on exactly how these resources are to be used.
I hope this helps you at least a little bit.
You could consider using Doctrine 2. It's an ORM that does not use the ActiveRecord pattern.
In Doctrine, your models (entities) are all just normal PHP objects with zero knowledge of the database. You use mapping (xml, yaml or annotations) to tell Doctrine how they appear in the database, and the Entity Manager and repositories are used as a gateway for persisting entities or doing other database actions.

Doctrine - self-referencing entity - disable fetching of children

I have a very simple entity(WpmMenu) that holds menu items connected to one another in a self-referencing relationship (adjecent list it's called)?
so in my entity I have:
protected $id
protected $parent_id
protected $level
protected $name
with all the getters/setters the relationships are:
/**
* #ORM\OneToMany(targetEntity="WpmMenu", mappedBy="parent")
*/
protected $children;
/**
* #ORM\ManyToOne(targetEntity="WpmMenu", inversedBy="children", fetch="LAZY")
* #ORM\JoinColumn(name="parent_id", referencedColumnName="id", onUpdate="CASCADE", onDelete="CASCADE")
*/
protected $parent;
public function __construct() {
$this->children = new ArrayCollection();
}
And everything works fine. When I render the menu tree, I get the root element from the repository, get its children, and then loop through each child, get its children and do this recursively until I have rendered each item.
What happens (and for what I am seeking a solution)is this:
At the moment I have 5 level=1 items and each of these items have 3 level=2 items attached (and in the future I will be using level=3 items as well). To get all elements of my menu tree Doctrine executes:
1 query for the root element +
1 query to get the 5 children(level=1) of the root element +
5 queries to get the 3 children(level=2) of each of the level 1 items +
15 queries (5x3) to get the children(level=3) of each level 2 items
TOTAL: 22 queries
So, I need to find a solution for this and ideally I would like to have 1 query only.
So this is what I am trying to do:
In my entities repository(WpmMenuRepository) I use queryBuilder and get a flat array of all menu items ordered by level. Get the root element(WpmMenu) and add "manually" its children from the loaded array of elements. Then do this recursively on children. Doing this way I could have the same tree but with a single query.
So this is what I have:
WpmMenuRepository:
public function setupTree() {
$qb = $this->createQueryBuilder("res");
/** #var Array */
$res = $qb->select("res")->orderBy('res.level', 'DESC')->addOrderBy('res.name','DESC')->getQuery()->getResult();
/** #var WpmMenu */
$treeRoot = array_pop($res);
$treeRoot->setupTreeFromFlatCollection($res);
return($treeRoot);
}
and in my WpmMenu entity I have:
function setupTreeFromFlatCollection(Array $flattenedDoctrineCollection){
//ADDING IMMEDIATE CHILDREN
for ($i=count($flattenedDoctrineCollection)-1 ; $i>=0; $i--) {
/** #var WpmMenu */
$docRec = $flattenedDoctrineCollection[$i];
if (($docRec->getLevel()-1) == $this->getLevel()) {
if ($docRec->getParentId() == $this->getId()) {
$docRec->setParent($this);
$this->addChild($docRec);
array_splice($flattenedDoctrineCollection, $i, 1);
}
}
}
//CALLING CHILDREN RECURSIVELY TO ADD REST
foreach ($this->children as &$child) {
if ($child->getLevel() > 0) {
if (count($flattenedDoctrineCollection) > 0) {
$flattenedDoctrineCollection = $child->setupTreeFromFlatCollection($flattenedDoctrineCollection);
} else {
break;
}
}
}
return($flattenedDoctrineCollection);
}
And this is what happens:
Everything works out fine, BUT I end up with each menu items present twice. ;) Instead of 22 queries now I have 23. So I actually worsened the case.
What really happens, I think, is that even if I add the children added "manually", the WpmMenu entity is NOT considered in-sync with the database and as soon as I do the foreach loop on its children the loading is triggered in ORM loading and adding the same children that were added already "manually".
Q: Is there a way to block/disable this behaviour and tell these entities they they ARE in sync with the db so no additional querying is needed?
With immense relief (and a lots of learning about Doctrine Hydration and UnitOfWork) I found the answer to this question. And as with lots of things once you find the answer you realize that you can achieve this with a few lines of code. I am still testing this for unknown side-effects but it seems to be working correctly.
I had quite a lot of difficulties to identify what the problem was - once I did it was much easier to search for an answer.
So the problem is this: Since this is a self-referencing entity where the entire tree is loaded as a flat array of elements and then they are "fed manually" to the $children array of each element by the setupTreeFromFlatCollection method - when the getChildren() method is called on any of the entities in the tree (including the root element), Doctrine (NOT knowing about this 'manual' approach) sees the element as "NOT INITIALIZED" and so executes an SQL to fetch all its related children from the database.
So I dissected the ObjectHydrator class (\Doctrine\ORM\Internal\Hydration\ObjectHydrator) and I followed (sort of) the dehydration process and I got to a $reflFieldValue->setInitialized(true); #line:369 which is a method on the \Doctrine\ORM\PersistentCollection class setting the $initialized property on the class true/false. So I tried and IT WORKS!!!
Doing a ->setInitialized(true) on each of the entities returned by the getResult() method of the queryBuilder (using the HYDRATE_OBJECT === ObjectHydrator) and then calling ->getChildren() on the entities now do NOT trigger any further SQLs!!!
Integrating it in the code of WpmMenuRepository, it becomes:
public function setupTree() {
$qb = $this->createQueryBuilder("res");
/** #var $res Array */
$res = $qb->select("res")->orderBy('res.level', 'DESC')->addOrderBy('res.name','DESC')->getQuery()->getResult();
/** #var $prop ReflectionProperty */
$prop = $this->getClassMetadata()->reflFields["children"];
foreach($res as &$entity) {
$prop->getValue($entity)->setInitialized(true);//getValue will return a \Doctrine\ORM\PersistentCollection
}
/** #var $treeRoot WpmMenu */
$treeRoot = array_pop($res);
$treeRoot->setupTreeFromFlatCollection($res);
return($treeRoot);
}
And that's all!
Add the annotation to your association to enable eager loading. This should allow you to load the entire tree with only 1 query, and avoid having to reconstruct it from a flat array.
Example:
/**
* #ManyToMany(targetEntity="User", mappedBy="groups", fetch="EAGER")
*/
The annotation is this one but with the value changed
https://doctrine-orm.readthedocs.org/en/latest/tutorials/extra-lazy-associations.html?highlight=fetch
You can't solve this problem if using adjacent list. Been there, done that. The only way is to use nested-set and then you would be able to fetch everything you need in one single query.
I did that when I was using Doctrine1. In nested-set you have root, level, left and right columns which you can use to limit/expand fetched objects. It does require somewhat complex subqueries but it is doable.
D1 documentation for nested-set is pretty good, I suggest to check it and you will understand the idea better.
This is more like a completion and more cleaner solution, but is based on the accepted answer...
The only thing needed is a custom repository that is going to query the flat tree structure, and then, by iterating this array it will, first mark the children collection as initialized and then will hydratate it with the addChild setter present in the parent entity..
<?php
namespace Domain\Repositories;
use Doctrine\ORM\EntityRepository;
class PageRepository extends EntityRepository
{
public function getPageHierachyBySiteId($siteId)
{
$roots = [];
$flatStructure = $this->_em->createQuery('SELECT p FROM Domain\Page p WHERE p.site = :id ORDER BY p.order')->setParameter('id', $siteId)->getResult();
$prop = $this->getClassMetadata()->reflFields['children'];
foreach($flatStructure as &$entity) {
$prop->getValue($entity)->setInitialized(true); //getValue will return a \Doctrine\ORM\PersistentCollection
if ($entity->getParent() != null) {
$entity->getParent()->addChild($entity);
} else {
$roots[] = $entity;
}
}
return $roots;
}
}
edit: the getParent() method will not trigger additional queries as long as the relationship is made to the primary key, in my case, the $parent attribute is a direct relationship to the PK, so the UnitOfWork will return the cached entity and not query the database.. If your property doesn't relates by the PK, it WILL generate additional queries.

Activerecord-association: create new object (find class)

I have an model with a relation, and I want to instantiate a new object of the relations type.
Example: A person has a company, and I have a person-object: now I
want to create a company-object.
The class of the companyobject is defined in the relation, so I don't think I should need to 'know' that class, but I should be able to ask the person-object to provide me with a new instance of type company? But I don't know how.
This is -I think- the same question as New model object through an association , but I'm using PHPActiveRecord, and not the ruby one.
Reason behind this: I have an abstract superclass person, and two children have their own relation with a type of company object. I need to be able to instantiate the correct class in the abstract person.
A workaround is to get it directly from the static $has_one array:
$class = $this::$has_one[1]['class_name'];
$company = new $class;
the hardcoded number can of course be eliminated by searching for the association-name in the array, but that's still quite ugly.
If there is anyone who knows how this is implemented in Ruby, and how the phpactiverecord implementation differs, I might get some Ideas from there?
Some testing has revealed that although the "search my classname in an array" looks kinda weird, it does not have any impact on performance, and in use it is functional enough.
You can also use build_association() in the relationship classes.
Simplest way to use it is through the Model's __call, i.e. if your relation is something like $person->company, then you could instantiate the company with $company = $person->build_company()
Note that this will NOT also make the "connection" between your objects ($person->company will not be set).
Alternatively, instead of build_company(), you can use create_company(), which will save a new record and link it to $person
In PHPActiveRecord, you have access to the relations array. The relation should have a name an you NEED TO KNOW THE NAME OF THE RELATIONSHIP/ASSOCIATION YOU WANT. It doesn't need to be the classname, but the classname of the Model you're relating to should be explicitly indicated in the relation. Just a basic example without error checking or gritty relationship db details like linking table or foreign key column name:
class Person extends ActiveRecord\Model {
static $belongs_to = array(
array('company',
'class_name' => 'SomeCompanyClass')
);
//general function get a classname from a relationship
public static function getClassNameFromRelationship($relationshipName)
foreach(self::$belongs_to as $relationship){
//the first element in all relationships is it's name
if($relationship[0] == $relationshipName){
$className = null;
if(isset($relationship['class_name'])){
$className = $relationship['class_name'];
}else{
// if no classname specified explicitly,
// assume the clasename is the relationship name
// with first letter capitalized
$className = ucfirst($relationship);
}
return $className
}
}
return null;
}
}
To with this function, if you have a person object and want an object defined by the 'company' relationship use:
$className = $person::getClassNameFromRelationship('company');
$company = new $className();
I'm currently using below solution. It's an actual solution, instead
of the $has_one[1] hack I mentioned in the question. If there is a
method in phpactiverecord I'm going to feel very silly exposing
msyelf. But please, prove me silly so I don't need to use this
solution :D
I am silly. Below functionality is implemented by the create_associationname call, as answered by #Bogdan_D
Two functions are added. You should probably add them in the \ActiveRecord\Model class. In my case there is a class between our classes and that model that contains extra functionality like this, so I put it there.
These are the 2 functions:
public function findClassByAssociation($associationName)
Called with the name of the association you are looking for.
Checks three static vars (has_many,belongs_to and has_one) for the association
calls findClassFromArray if an association is found.
from the person/company example: $person->findClassByAssociation('company');
private function findClassFromArray($associationName,$associationArray)
Just a worker-function that tries to match the name.
Source:
/**
* Find the classname of an explicitly defined
* association (has_one, has_many, belongs_to).
* Unsure if this works for standard associations
* without specific mention of the class_name, but I suppose it doesn't!
* #todo Check if works without an explicitly set 'class_name', if not: is this even possible (namespacing?)
* #todo Support for 'through' associations.
* #param String $associationName the association you want to find the class for
* #return mixed String|false if an association is found, return the class name (with namespace!), else return false
* #see findClassFromArray
*/
public function findClassByAssociation($associationName){
//$class = $this::$has_one[1]['class_name'];
$that = get_called_class();
if(isset($that::$has_many)){
$cl = $this->findClassFromArray($associationName,$that::$has_many);
if($cl){return $cl;}
}
if(isset($that::$belongs_to)){
$cl = $this->findClassFromArray($associationName,$that::$belongs_to);
if($cl){return $cl;}
}
if(isset($that::$has_one)){
$cl = $this->findClassFromArray($associationName,$that::$has_one);
if($cl){return $cl;}
}
return false;
}
/**
* Find a class in a php-activerecord "association-array". It probably should have a specifically defined class name!
* #todo check if works without explicitly set 'class_name', and if not find it like standard
* #param String $associationName
* #param Array[] $associationArray phpactiverecord array with associations (like has_many)
* #return mixed String|false if an association is found, return the class name, else return false
* #see findClassFromArray
*/
private function findClassFromArray($associationName,$associationArray){
if(is_array($associationArray)){
foreach($associationArray as $association){
if($association['0'] === $associationName){
return $association['class_name'];
}
}
}
return false;
}

Generating next sequence value manually in Doctrine 2

What would be the easiest way to generate nextval for some particular sequence with given name?
The annotation solution with specifying
* #ORM\GeneratedValue(strategy="SEQUENCE")
* #ORM\SequenceGenerator(sequenceName="sq_foobar", allocationSize="1", initialValue="1")
doesn't satisfy me, as long as there is some more complex logic involved: in some cases I need to retrieve nextval, in other - I would go with the value retrieved from another sources (not sequence).
So I hope there is a way to retrieve a sequence nextval manually in entity's constructor.
Just in case someone else lands on this question (like I did):
The pull request #Florian mentioned made it into doctrine now. Although documentation seems to still lack any information for the CUSTOM id generator strategy. Only part I found where CUSTOM option for IdGenerator is mentioned is at GeneratedValue description. If I missed it, please correct me in the comments.
Tough it can easily be implemented. Just create an class extending Doctrine\ORM\Id\AbstractIdGenerator:
namespace My\Namespace;
use Doctrine\ORM\Id\AbstractIdGenerator;
class MyIdGenerator extends AbstractIdGenerator
{
public function generate(\Doctrine\ORM\EntityManager $em, $entity)
{
// Create id here
$id = <do some logic>;
return $id;
}
}
Then add it to your id description in the doctrine entity configuration (YAML example):
My\Bundle\Entity\MyEntity:
type: entity
id:
id:
type: bigint
unique: true
generator:
strategy: CUSTOM
customIdGenerator:
class: 'My\Namespace\MyIdGenerator'
fields:
otherField: ....
If you use Annotations instead of YAML, the entity configuration should look like this (untested):
/**
* #Id
* #Column(type="integer")
* #GeneratedValue(strategy="CUSTOM")
* #CustomIdGenerator(class="My\Namespace\MyIdGenerator")
*/
public $id;
And thats all ;)
There are two possibilities getting sequence nextval in Doctrine2:
Use Doctrine ORM SequenceGenerator
use Doctrine\ORM\Id\SequenceGenerator;
$sequenceName = 'file_id_seq';
$sequenceGenerator = new SequenceGenerator($sequenceName, 1);
$newId = $sequenceGenerator->generate($entityManager, $entity);
// $entity in this case is actually not used in generate() method, so you can give any empty object, or if you are not worried about editor/IDE warnings, you can also specify null
Use native SQL
$sequenceName = 'file_id_seq';
$dbConnection = $entityManager->getConnection();
$nextvalQuery = $dbConnection->getDatabasePlatform()->getSequenceNextValSQL($sequenceName);
// $nextvalQuery is now following string "SELECT NEXTVAL('file_id_seq')"
$newId = (int)$dbConnection->fetchColumn($nextvalQuery);
Then I think you should implement your own Identitfer Generator.
The easyest would be to override the Doctrine\ORM\Id\SequenceGenerator class to handle your specific case.
You then have to register this generator in the class metadata using Doctrine ORM API.
Some links: http://ranskills.wordpress.com/2011/05/26/how-to-add-a-custom-id-generation-strategy-to-doctrine-2-1/
https://github.com/doctrine/doctrine2/pull/206
I have symfony 6 with doctrine-orm 2.13 and works with code,
In SomeEntityRepository created function:
public function fetchSeqId(EntityManagerInterface $entityManager){
$dbConnection = $entityManager->getConnection();
$nextValQuery = $dbConnection->getDatabasePlatform()->getSequenceNextValSQL('some_id_seq');
$id = (int) $dbConnection->executeQuery($nextValQuery)->fetchOne();
return $id;
}
and use in controller as:
$repository = $this->entityManager->getRepository(SomeEntity::class);
$id= $repository->fetchSeqId($this->entityManager);

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