Being new to app design and coding I have the following question related to Class design. I have a class by the name of Art Object which has the following other attributes:
'Type' such as 'Painting', 'Sculpture', 'Drawing', 'Collage' etc.
Categories such as 'Modern (Art Nouveau)', 'Art Deco', 'Gothic' etc.
Now my question is, how do I design this. In my opinion I have two options:
Create a separate model , say ArtObjectTypes and have all the CRUD operations. And then establish relation between ArtObject and ArtObjectType.
Create a separate model , say CustomFields on which I can have all CRUD operations. The benefit in this case is that in future I will be able to generate more custom types attach with the ArtObject or any other Object.
Please advise which of the above options I should go for and why. Also, please do bring up if there is another choice.
First ask yourself how you would organize this in your database.
Draw a schema like this:
Define the relations, the foreign keys, and only then you should start implementing the models. A model in laravel corresponds to a table in your database.
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I have been using Laravel for a couple weeks now and I love the framework. However, with models is there any actual robust system? Creating models, like the user model, just seems to be string arrays of what you do and do not want modified in queries. The place I see validation of the models is in the controller (through $this->validate()) and/or migrations creating the tables.
I just wanted to know if there is a certain place I am missing or not implementing. My brain is referencing something like ASP.NET's decorators that add validation to data models. Thank you!
I have a doub about Laravel. The models are used to define the relationships between the models like hasMany, belongsTo, etc. Also the models are used to define the fillable fields. But he models are only for that? Because I already check some examples that it seems that some queries are executed in the models instead of the controller so Im not understanding if the models should also have the querying of the relationships or not. Can you give a help to understand better what is the correct use of models (what should be placed in the models)?
Its same way to execute queries on model or controller. Written queries in model make your controller more clean. We can write mutator, accessor or query scope in eloquent model. Correct me if I'm wrong.
Visit https://laravel.com/api/5.5/Illuminate/Database/Eloquent/Model.html
You can refer this documentation, it's quite helpful if you want to know deep basics and responsibilities about particular part in Laravel.
Models are mostly used to make an outlook of the data i.e what fields are going to be saved in the database and we also use it to associate the relationships with other related data as you already know but we also use it to alter the values that are either going in/out of the data base which you can check in the documentation in link bellow https://laravel.com/docs/5.6/eloquent-mutators
the main purpose is to divide the code between controller and model (were it best fit to be)
Let's say we are structuring an application with MVC (also, Stores/Services). SQL is used as the persistence mechanism. And memory efficiency is a major concern.
Obviously, we should take advantage of SQL queries and only ask for fields of our Model in theory object when they are needed.
For example, an mobile app may need to display a list of title for articles, while the body of the article doesn't get displayed until user taps on a specific title. In this case, we ask SQL for just the titles first.
The question is, what should the model object look like?
The solutions I can think of are:
Enhance the model with some states that indicate which fields are populated. This could also be archived by using nil/NULL/None values on unpopulated fields of the model object.
Split the theoretical model to multiple classes. Following the previous example, we could have an Article class and an ArticleDetail class, with a one-to-one relation.
Forget the Store object, let each model object lazy evaluate it's costly fields. The model would have to know about its persistence mechanism.
This should be a common problem. How do the ORM in your favorite frameworks/libraries resolve it? Any best practices?
I have programmed in Rails, Django, Zend, and CakePHP. Also, Wordpress and Drupal.
Now, I am "catching up to speed" in as fairly large application in CodeIgniter.
Typically, my experience with MVC frameworks, has led me to believe that Models represent business logic in reference to actual database tables. In the CodeIgniter docs and in the code base I'm dissecting I see models created that represent something as vague as a page. A lot of the business logic is written directly into those models and they incorporate other actual data models. I'm not sure this is ideal and following MVC.
Should models be created beyond data models?
Also, lets say I have a data model representing a user (user table in DB). In that user table there is a column called gender of the type enum('male', 'female'). Now I want to populate a dropdown with the gender options from the enum column.
Where is it most appropriate to put this logic?
The user model is an object used to represent a single user or row in the db... right? So it doesn't seem fitting to include a function in the user model/class called "get_gender_options", because, while the function is related to the user table, it is NOT relevant to a single user object. In Zend this kind of logic could be built into the form object itself.
There is not "right" answer, just one we can consider the most appropriate...
I would probably just put the "get_gender_options" in the model, rather than sticking it in the view for the form. To keep it DRY but not put it in the model, I would create a helper to hold this.
I am wondering how the models in code ignitor are suposed to be used.
Lets say I have a couple of tables in menu items database, and I want to query information for each table in different controllers. Do I make different model classes for each of the tables and layout the functions within them?
Thanks!
Models should contain all the functionality for retrieving and inserting data into your database. A controller will load a model:
$this->load->model('model_name');
The controller then fetches any data needed by the view through the abstract functions defined in your model.
It would be best to create a different model for each table although its is not essential.
You should read up about the MVC design pattern, it is used by codeigniter and many other frameworks because it is efficient and allows code reuse. More info about models can be found in the Codeigniter docs:
http://codeigniter.com/user_guide/general/models.html
CodeIgniter is flexible, and leaves this decision up to you. The user's guide does not say one way or the other how you should organize your code.
That said, to keep your code clean and easy to maintain I would recommend an approach where you try to limit each model to dealing with an individual table, or at least a single database entity. You certainly want to avoid having a single model to handle all of your database tables.
For my taste, CodeIgniter is too flexible here - I'd rather call it vague. A CI "model" has no spec, no interface, it can be things as different as:
An entity domain object, where each instance represents basically a record of a table. Sometimes it's an "anemic" domain object, each property maps directly to a DB column, little behaviour and little or no understanding of objects relationships and "graphs" (say, foreign keys in the DB are just integer ids in PHP). Or it can also be a "rich (or true) domain object", with all the business intelligence, and also knows about relations: say instead of $person->getAccountId() (returns int) we have $person->getAccount(); perhaps also knows how to persist itself (and perhaps also the full graph or related object - perhaps some notion of "dirtiness").
A service object, related to objects persistence and/or general DB querying: be a DataMapper, a DAO, etc. In this case we have typically one single instance (singleton) of the object (little or no state), typically one per DB table or per domain class.
When you read, in CI docs or forums, about , say, the Person model you can never know what kind of patter we are dealing with. Worse: frequently it's a ungly mix of those fundamentally different patterns.
This informality/vagueness is not specific to CI, rather to PHP frameworks, in my experience.