Laravel Eloquent

Introduction

Hello there!!

Today, we will learn about Eloquent and its uses in Lavarel. Many of the complicated queries required to deal with relationships, insert, update, and remove database records, as well as search, filter, and limit query results, are abstracted using Eloquent. In this article, we will understand Eloquent in Laraval thoroughly.

Laravel Eloquent

Laravel is a PHP framework based on MVC. The letter 'M' stands for 'Model' in MVC architecture. A Model is essentially a method for querying data to and from a database table. Using Eloquent ORM, Laravel offers a simple method to accomplish this. Every table has a Model that interacts with it.

Models are built in the app directory. You may also put the model anywhere, and it will be loaded automatically based on the composer.json file.

To generate the model, we may use the following command:

php artisan make:model Example

We can also create the model using database migration:

php artisan make:model Example -m

or

php artisan make:model Example -migration

Creating the model

1. Go to your project inside htdocs folder. Open the Git Bash window and enter the above command.

We can see that the model with name Example has been created successfully.

2. Below is created project in the app directory

Structure of the Model

The structure of the Model we just created is given below.

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Example extends Model
{
    use HasFactory;
}

This means that the Example class extends the use Illuminate\Database\Eloquent\Model.

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Table Names

We do not need to mention the table name for the Post model in laravel eloquent. Unless we supply the table name directly, the class's plural name( small case) will be used as the table name. In the given code, for example, the name of the class that operates on the table examples is Example. We may alternatively define the custom table by using the model class's $table property, as shown in the code below:

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Example extends Model
{
    use HasFactory;
    protected $table = 'examples';  
}

The $table property in the previous code indicates that the Example class is using the examples table.

Primary keys

According to the eloquent model, each table has a primary key called 'id.' We may override this convention by giving the $primarykey property an alternative name.

<?php  
namespace App;  
use Illuminate\Database\Eloquent\Model;  

Class SampleClass extends Model  
{  
    protected $primaryKey = 'example_id';  
/** 
     * primary key of the table 
*/
}

In eloquent, the primary key is always an auto-incremented integer value. If we wish to provide the primary key a non-incrementing value, we must set the $incrementing property to 'false.'

Read Data

Let us now learn to retrieve data from the database. We will understand this through an example.

1. We will first add two attributes to the class model.
   Example.php

<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
class Example extends Model
{
    use HasFactory;
    protected $table = 'examples'; 
    protected $primaryKey='id'; 
}

2. Adding the route to retrieve the data from the database.
    Web.php

<?php  
use App\Example;  
Route::get('/readdata',function(){  
$posts=Example::all();  
foreach($posts as $post)  
{  
  echo $example->body;  
  echo '<br>';  
}  
});

In the above code, we use the all() function to obtain all the records from the database, and then we use the foreach loop to extract the body name of all the rows in the database.

Reading data with constraints

1. If we want to get a specific record from the database, we use the find() function.

Route::get('/findfunc',function(){  
$posts=Example::find(2);  
return $examples->title;  
}); 

2. If we don't need to access the complete row, we may use the value() function to get the value of a single column.

Route::get('/findfunc',function(){  
$examples=Example::where('id',1)->value('title');  
return $examples;  
}); 

Insert data

Now we'll look at how to insert the data into a database. Consider the following example:

Route::get('/insertdata',function(){  
$example=new Example;  
$example->title='Sanjana';  
$example->body='QA Analyst';  
$example->save();  
}); 

Updating the Data with the save() method

Route::get('/updatedata',function(){  
  $example=Example::find(2);  
  $example->title='Akshita';  
  $example->body='Graphic Designer';  
  $example->save();  
  });

Delete Data

We will use the delete() function to remove data from the database, as illustrated below:

There are several methods for deleting the data.

1. The first approach is to use the find() and remove() functions.

Route::get('/finddelete',function(){  
$example=Example::find(3);  
$example->delete();  
});

This will delete the record having id 3.

2. The second approach is to use the destroy() function.

Route::get('/destroyfunc',function(){  
Example::destroy(4);  
});  
This will delete the record having id 4.
To destroy more than one row,
Route::get('/destroyfunc',function(){  
Example::destroy([5,6]);  
});

This will delete the record having ids 5 and 6.

3. The third option is to execute the query.

Route::get('/deletethroughquery',function(){  
Examplet::where('id',7)->delete();  
});

This will delete the record having id 7.

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