Laravel development: How to build a model using Laravel Eloquent?

Laravel is a popular PHP web framework that is popular due to its simplicity and ease of use. The Laravel framework is known for its implementation of the excellent Eloquent ORM, which is an Object-Relational Mini mapping that supports the use of PHP to define database models and provides easy database interaction based on these models.

This article will introduce in detail how to use Laravel Eloquent to build a model to interact with the database quickly and reliably.

What is Laravel Eloquent

Eloquent ORM is an ORM system built into the Laravel framework, which allows you to use PHP to interact with the database instead of directly operating data in MySQL statements. Eloquent maps a series of data tables to objects, so you can name and manipulate each field in the data table without directly executing SQL statements.

To use Laravel Eloquent ORM, you must configure the database connection before building the database model, as shown below.

<?php

use IlluminateSupportFacadesDB;

$connection = DB:：connection（）;
$name = $connection->getDatabaseName（）;

Generally speaking, the Laravel framework has already configured the database connection in the .env file. In local development, you generally only need to keep the default connection.

How to build models using Laravel Eloquent

Laravel Eloquent ORM provides a simple and powerful way to define models without writing complex SQL statements.

In Laravel, each Eloquent model is associated with a database table. We can use the php artisan command to create the database migration file, and then use the php artisan make:model command to create an Eloquent model.

The following example shows how to create a model:

php artisan make:model Example

This will create an Example.php file in the app directory. The following is the specific code:

<?php

namespace App;

use IlluminateDatabaseEloquentModel;

class Example extends Model
{
    //
}

Use With this simple model, we can start to define and model the data table. The specific modeling is as follows:

Schema::create(`example`, function ($table) {
    $table->increments(`id`);
    $table->string(`title`);
    $table->string(`body`);
    $table->timestamps();
});

After defining the model, we can build the query through Eloquent's query builder. The following is a Laravel Example of Eloquent query:

$example = Example::find(1);

In this query, Example::find(1)reads the records in the default table example and returns a AppExampleModel instance. On this model instance we can execute internal functions or properties, for example:

$title = $example->title;

The above code will output the value of the title column of the record with id 1 in the table.

Add association to data table model

In Laravel Eloquent ORM, we can express the relationship between data models by adding association relationships, such as the association between the following two models:

class Country extends Model
{
    public function user()
    {
        return $this->hasMany(User::class);
    }
}

class User extends Model
{
    public function country()
    {
        return $this->belongsTo(Country::class);
    }
}

In this model, a country can have multiple users, so CountryModelhasMany is associated with the user model; on the other hand, a user can only come from one country, so the model User belongs to the country model using the belongsTo method.

By defining these relationships, we can easily obtain the corresponding association model using the with method when querying, for example:

$countries = Country::with('user')->get();

In the above query, Country::with('user')Returns the user record of the association defined by Country::user(). These collections can be accessed in the returned collection, for example:

foreach ($countries as $country) {
    foreach ($country->user as $user) {
        echo $user->name;
    }
}

Summary

Laravel Eloquent ORM is one of the best features of the Laravel framework, which simplifies the complexities of interacting with the database for developers. . By setting up a database connection, creating models, and defining relationships, we can easily interact with and retrieve data from the database. When using Laravel, remember to use the Laravel Eloquent ORM to build database models more efficiently and streamlinedly.

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