I'm after some code advice. I've got two models which are dependent on each other. When one of the models gets deleted I want to make sure both records in the database are deleted.
I handle this in one direction using foreign keys so if the parent gets deleted to. But as these rows are both dependent on each other I need the same functionality to happen in the child.
In the child model I've overloaded the delete method so it looks like this:
public function delete() {
$cameraTransaction = $this->dbConnection->beginTransaction();
try
{
$this->ftpuser->delete();
if($this->beforeDelete())
{
$result=$this->deleteByPk($this->getPrimaryKey())>0;
$this->afterDelete();
}
$cameraTransaction->commit();
}
catch(Exception $e) // an exception is raised if a query fails
{
$cameraTransaction->rollBack();
}
}
I've tested and this seems to work well. I wondered if an expert / guru could confirm whether I've done the right thing :)
Thanks
Alan
I think you are doing it right. You can make it something more general.
Every model has relations defined, make some(or all) the relations deletable. You have to flag them ( in someway) deletable along with current record.
I would define a new function besides relations() in the model.
function deletableRelations() {
return array('ftpuser', 'childs', .....);
}
and define some generic function (please include DB transactions in this function.)
function DeleteRelationships($model) {
foreach( $model->deletableRelations() as $relation ) {
if( $model->$relation == null) continue;
if( is_array($model->$relation)) {
foreach( $model->$relation as $relRecord ) {
$relRecord->delete();
}
}
else {
$model->$relation->delete();
}
}
}
And this generic function can be used any of your models.
Make sure that recursion does not happen here (i.e. parent deletes child ... but child also tries to delete parent. )
Related
I have 2 models, store and dvd with many to many relationship
dvd model:
public function stores() {
return $this->belongsToMany('App\store');
}
store model:
public function dvds ( ) {
return $this->belongsToMany('App\dvd');
}
Then, in controller, when I need fetch data from both models, I use code like this:
$res_store = store::orderBy("id","desc")->get();
foreach( $res_store as $row ) {
$dvds = $row->dvds()->get();
foreach ($dvds as $dvd) {
// echo columns here
}
}
This works, but my question is, I'm doing this in correct way? I'm asking because it seems 2 loops for this simple relation is somehow inefficient.
No, this is not the right way.
When looping over a $store, you can access the associated $dvd records via $store->dvds; there is no need to call $row->dvds()->get(), as that is executing a new query with the same result of $store->dvds. Full code should simply be:
$stores = Store::with("dvds")->orderBy("id", "DESC")->get();
foreach($stores AS $store){
foreach($store->dvds AS $dvd){
... // Do something with `$dvd`
}
}
The ::with("dvds") clause is known as "Eager loading", and prevents $store->dvds from needing execute another query behind the scenes.
Also, please name your models correctly. Classes in PHP are StudlyCase, so Store and DVD, not store and dvd.
I have a model in Yii that contains an array of another model type. I am then trying to validate that no duplicate emails are filled out in a form, where you can fill out for n number of persons at the same time.
My current approach is to trigger a custom validation of the "outer" model that holds all the entrants, however, that model is not accessible in the view, only the array of entrants is, and if I then trigger the error on the "outer" model, it will not be displayed to the user. Therefore I would like to trigger it for the first entrant that violates the rule, but how do I go about doing that?
My code that attempts this, looks like this so far:
/*
* Custom validation rule to hinder the same e-mail being used twice.
*/
public function noRepeatingEmails($attribute, $params)
{
if (!isset($attribute)) return;
$emails = array();
foreach($this->$attribute as $user)
{
if (isset($user) && strlen(trim($user->email)) != 0)
{
$emailToAdd = strtolower(trim($user->email));
if (in_array($emailToAdd, $emails))
{
$this->addError($user, '<my error message>');
return;
}
else
{
$emails[] = $emailToAdd;
}
}
}
}
This only results in a code 500 error though:
Illegal offset type
I presume that is because it is looking for the property "user" in my model, rather than adding an error to "$user" object.
How do I best accomplish this?
I have a .NET background, so I am probably doing loads wrong here however.
If I understood correctly from your comment, you want to validate your model before saving it. For this purpose, CActiveRecord provides beforeSave() method. You need to put this method inside your model:
protected function beforeSave()
{
if(parent::beforeSave())
{
if(/* Your validation goes here*/)
return true;
else
return false
}
else
return false;
}
When the result of this method is true, save() method will be called. Otherwise save() method won't be called and therefore no record will be saved into your database.
So, I was trying to implement this answer for my other question on the same subject... and it keeps givin me the exceeded time error. Any clues?
This is on my product model. It inherits from Eloquent.
public function newQuery($excludeDeleted = true)
{
$user_permission = Auth::user()->permissions;
if( $user_permission->master )
return parent::newQuery();
else if( $user_permission->web_service )
{
$allowed_ids = array();
foreach( $user_permission->allowed_products()->get() as $allowed)
$allowed_ids[] = $allowed->id;
return parent::newQuery()->whereIn('id', $allowed_ids);
}
return parent::newQuery();
}
If the user is master there is no need to query scope on the request. But, if it isn't then I need to filter by the logged user's permissions.
UPDATE:
I tried the following code in a controller and it works alright:
$user_permission = Auth::user()->permissions;
echo "<PRE>"; print_r($user_permission->allowed_products()->get()); exit;
UPDATE 2:
Guys, I just found out that the problem was in this peace of code:
$allowed = Auth::user()->permissions()->first()->allowed_products()->get()->list('id');
It somehow give me an Maximum execution time of 30 seconds exceeded. If I put the exact same code in a controller, works like a charm, though! I also tried to put it in a scope, also worked. This it's really grinding my gears!
Elloquent has a function called newQuery. Controller does not. When you implement this function in a Model you are overriding the one in Elloquent. If you then invoke Elloquent methods that need a new query for your model before they can return, like ->allowed_products()->get(). Then you are calling your own newQuery() method recursively. Since the user permissions have not changed, this results in infinite recursion. The only outcome can be a timeout because it will keep on trying to determine a filtered product list which causes your newQuery() method to be called, which tries to determine the filtered product list before returning the query, and so on.
When you put the method into a Controller, it is not overriding the Elloquent newQuery method so there is no infinite recursion when trying to get the allowed_product list.
It would be more efficient to apply the filter to the product query based on whether the id is in the user's allowed_products() list using ->whereExists() and build up the same query as allowed_products() except now add condition that id from the query you are filtering is equal to the product id in the allowed products query. That way the filtering is done in the database instead of PHP and all is done in the same query so there is no recursion.
I don't see how your update code works. Illuminate\Database\Eloquent\Collection does not have any magic methods to call the relation functions, you should get an undefined method error trying to do that.
Can you try something like
public function newQuery($excludeDeleted = true)
{
// Returns `Illuminate\Database\Eloquent\Collection`
$user_permission = Auth::user()->permissions;
if ($user_permission->master)
{
return parent::newQuery();
}
else if ($user_permission->web_service)
{
// If here you was to call $user_permission->allowed_products()->get() not much is going to happen, besides probably getting an undefined method error.
$allowed_ids = Auth::user()->permissions()->allowed_products()->get()->lists('id');
return parent::newQuery()->whereIn('id', $allowed_ids);
}
return parent::newQuery();
}
Update: as per comments below I believe the problem is due to newQuery() being called multiple times as the code works just fine when called once in a controller. When this is applied to every query there is no need to collect all the IDs over and over again (assuming they're not going to change each time you call for them). Something such as the below will allow you to store these and only process them once per request rather than every time a query is run.
private $allowed_ids_cache = null;
public function newQuery($excludeDeleted = true)
{
$user_permission = Auth::user()->permissions;
if ($user_permission->master)
{
return parent::newQuery();
}
else if ($user_permission->web_service)
{
if ($this->allowed_ids_cache === null)
{
$this->allowed_ids_cache = Auth::user()->permissions()->allowed_products()->get()->lists('id');
}
return parent::newQuery()->whereIn('id', $this->allowed_ids_cache);
}
return parent::newQuery();
}
I've an ORM model (PHP Active Record), say, for a blogging system. I've something that's a post model that stores the number of likes. The post could either be a picture or quote (say), and they are different tables (and hence models).
The schema is that a post holds data like number of shares, likes, description, etc. along with either a picture or a quote.
So when writing getters for the post model I'm having to write
public function getX() {
if ($this->isPicture()) {
return $this->picture->getX();
}
else if ($this->isQuote()) {
return $this->quote->getX()
}
else {
return self::DEFAULT_X
}
}
I'm currently having to write this structure for many getter. Is there something I can do to avoid that?
PS: Tagged as PHP because that's my code in.
EDIT
Changed comments to code.
This is a model (and a corresponding table in the DB) that has more data than just a picture and quote. Example, description that's part of the post and doesn't reside on either the picture or the quote.
There's tables for pictures and quotes.
Using PHP Active Record and each of the three classes extends the generic model class provided by PHP Active Record.
The picture model has it's own data. Same for quote.
To expand on the idea of the Strategy pattern mentioned in the comments:
class Post {
// get the correct 'strategy'
public function getModel() {
if ($this->isPicture()) {
return $this->picture;
}
if ($this->isQuote()) {
return $this->quote;
}
return null;
}
// using the strategy
public function getX() {
$model = $this->getModel();
if (null === $model) {
return self::DEFAULT_X;
}
return $model->getX();
}
}
Each strategy would presumably implement the same interface as the Post class for exposing those getters. Even better would be to provide a default strategy (rather than returning null) and have that return the default values. That way, the null check in each getter becomes redundant.
An alternative approach to this is a very basic form of metaprogramming. The idea is that you go a level higher than calling your methods by hand, and let the code do it for you.
(Assume that the method definitions are all part of Post)
public function getX($model = null) {
if ($model) return $model->getX();
else return self::DEFAULT_X;
}
// usage
$postModel->getX($pictureModel);
What's happening here is that, in this single instance of getX in your Post model, you're passing in the name of another class, and executing the `getX' method on that instance (if it exists and is callable).
You can extend this in other ways. For example, maybe you don't want to pass an instance in, when the method can do it anyway:
public function getX($model_name = null) {
if ($model_name && $class_exists($model_name) && is_callable(array($model_name, 'getX')) {
$model = new $model_name;
return $model->getX();
} else {
return self::DEFAULT_X;
}
}
// usage
$postModel->getX('Picture');
In this instance, you pass the model in as a string, and the method will do the rest. While this makes it quicker to get what you want, you might find that you don't want to work with fresh instances all the time (or you can't), so there's a bit of a trade-off with this 'convenient' way.
That still doesn't fully solve your problem, though, since you still have to repeat that for each getter, over and over again. Instead, you can try something like this:
public function __call($method, $args) {
$class = $args[0];
if (class_exists($class) && is_callable(array($class, $method))) {
$model = new $class;
return $model->$method();
}
}
// usage
$postModel->getX('Picture');
$postModel->getY('Quote');
$postModel->getZ('Picture');
If you call a function that doesn't exist on the Post model, that magic method will be called, and it'll fire up a new instance of the model name you supply as an argument, and call the getWhatever method on it, if it exists.
It's important to note that you must not define these getters in Post, unless you want to override the methods in the other classes.
There is still the problem of this creating new instances all the time, though, and to remedy this you can use a bit of dependency injection. This means that you let the Post class contains a list of other instances of classes that it wants to use in future, so you can add and remove them at will.
This is what I would consider the actual solution, with the other examples hopefully showing how I've got here (will edit to clarify things, of course).
public $models = array();
public function addModel($instance) {
$this->models[get_class($instance)] = $instance;
}
public function __call($method, $args) {
$class = $args[0];
if (array_key_exists($class, $this->models)) {
$model = $this->models[$class];
if (is_callable(array($model, $method)) {
return $model->$method();
}
}
}
// usage
$this->addModel($pictureModel);
$this->addModel($quoteModel);
$this->getX('Picture');
$this->getY('Quote');
Here, you're passing in your existing instances of models into the Post class, which then stores them in an array, keyed by the name of the class. Then, when you use the class as described in the last example, instead of creating a new instance, it will use the instance it has already stored. The benefit of this is that you might do things to your instances that you'd want reflected in the Post model.
This means that you can add as many new models as you like that need to plug into Post, and the only thing you need to do is inject them with addModel, and implement the getters on those models.
They all require you to tell the class what models to call at some point or another. Since you have an array of dependent models, why not add a way to get everything?
public function __call($method, $args) {
$class = $args[0];
if (array_key_exists($class, $this->models)) {
$model = $this->models[$class];
if (is_callable(array($model, $method)) {
return $model->$method();
}
} elseif ($class === 'all') {
// return an array containing the results of each method call on each model
return array_map(function($model) use ($method) {
if (is_callable(array($model, $method) return $model->$method();
}, $this->models);
}
}
// usage
$postModel->getX('all');
Using this, you'll get an array containing the return values of each getX method on each model you added with addModel. You can create pretty powerful functions and classes that do all this stuff without you having to repeat tedious logic.
I have to mention that these examples are untested, but at the very least I hope the concept of what you can do has been made clear.
Note:
The same thing can be applied to __GET and __SET methods, too, which are used for accessing properties. It's also worth saying that there may be the slight risk of a library already using these magic methods, in which case you'll need to make the code a little more intelligent.
I'm writing my first application with Zendframework.
My question is about the Model–View–Controller (MVC) architectural pattern.
I currently have a model with refer to a database table.
Here's the classes that I currently have :
Model_Person
Model_PersonMapper
Model_DbTable_Person
Now, I see a lot of examples on the net, but all of them are simple cases of insert/update/delete.
In my situation, I have to check if a person exists, and if it doesn't, I have to insert it and retrieve the ID (I know save return the Id, but it's not exactly what I have to do, this is and example).
It's quit simple, but I want to know where to put the database logic for all the others specific cases. Some others cases might involve checks across other tables or ... whatever !
Should I add all the specific functions in my Model_XXXXMapper with something that would be very specific with the current validation/process that I want to do? like a function getIdOfThePersonByNameOrInsertIfNotExists() (sample name of course!!!)
Or should it reside in the controller with some less specifics access to my model would be validated?
In other word, where do I put all the data specifics functions or check ?
I think the real work should occur in your model objects, not in the controller. Any selects/creates that start with the person table would be in the DbTable_Person object, things like:
// DbTable_Person
// returns sets of or single Person objects
public function createByName( $name ) // perhaps throws exception if name already exists
public function findById( $id )
public function findByName( $name )
public function findHavingAccount( $account_id ) // references another table
// controller
// with your example, like what Galen said,
// I would let the controller handle this logic
$person = $person_table->findByName($name);
if ( !$person ) {
$person = $person_table->createByName($name);
}
if ( !$person ) { throw new Zend_Exception('huh?'); }
$id = $person->id; // you wanted the ID
I would definitely split the function up into search/create functions.
Here's a basic implementation...
$personTG = new Model_PersonTableGateway;
if ( !$person = $personTG->findByName( $name ) ) {
$person = new Model_Person;
$person->name = $name;
// other variables
$newPersonId = $personTG->create( $person ); // creates a new person
}
I use table gateway. You can substitute your class for the TG.
You can have the create() function return just the id of the newly created person, or the entire person...it's up to you.
You might be interested in Zend_Validate_Db_NoRecordExists and its sister. If you are using Zend_Form you can add this validator to your form element. Many folks use Zend_Form to validate and filter data before they reach the domain model.
If you are not using Zend_Form, you can simply use this validation class in your service layer. A simple service class could be something like
`
class Service_Person_Validate
{
public function creatable($data)
{ // return true|false
}
}