How to implement add, delete, modify and check functions in laravel5

Laravel is one of the most popular PHP frameworks. It provides rich features and easy-to-use tools to help developers build excellent web applications faster. This article will introduce the addition, deletion, modification and query functions of Laravel5.

Adding data

It is very easy to add data using Laravel5. We need to use Eloquent ORM to access the database. Eloquent ORM is Laravel's default ORM and can easily map database tables into PHP objects. The following is an example:

$user = new User;
$user->name = 'John';
$user->email = 'john@example.com';
$user->save();

This sample code creates a User object, sets the name and email attributes, and finally calls the save() method to save the data to the database.

In Laravel, you can use forms to create data. For example, we can use the following code in the template:

<form method="POST" action="/users">
  {{ csrf_field() }}
  <input type="text" name="name" />
  <input type="text" name="email" />
  <button type="submit">Save</button>
</form>

This code creates an HTTP POST request and sends the data to the /users route. The route will call the store() method defined in the UserController controller class, which uses Eloquent ORM to create a new User object and save it to the database. Note the {{ csrf_field() }} in the code, which is a CSRF token used to prevent cross-site attacks.

Query data

Laravel provides a variety of ways to query data. The most commonly used of these is the Eloquent ORM query builder. Using the query builder, developers can take full advantage of Laravel's Eloquent ORM capabilities.

The following is a sample code for querying data:

$users = DB::table('users')->where('email', '=', 'john@example.com')->get();
foreach ($users as $user) {
    echo $user->name;
}

This code queries users with email address 'john@example.com' and prints their names.

An even more powerful way to query data is to use Eloquent ORM's relational query. Relational queries allow us to retrieve data related to other models and retrieve multiple relationships in a single query.

The following is an example:

class User extends Model
{
    public function posts()
    {
        return $this->hasMany('App\Post');
    }
}

$users = User::with('posts')->get();

This code queries the User model and its Posts association, and loads them all at once. This avoids the N 1 query problem.

Update data

Updating data is also very simple. We can use Eloquent ORM or query builder to update data. Here is an example using Eloquent ORM:

$user = User::where('email', '=', 'john@example.com')->first();
$user->name = 'Jane';
$user->save();

This code finds users with email address 'john@example.com' and updates their name for 'Jane'.

If we want to update multiple records at once, we can use the query builder:

$affected = DB::table('users')
              ->where('id', 1)
              ->update(['votes' => 1]);

This code updates the number of votes for the user with id 1 to 1.

Deleting Data

To delete data, we can use Eloquent ORM or query builder. Here is an example using Eloquent:

$user = User::where('email', '=', 'john@example.com')->first();
$user->delete();

This code finds users with email address 'john@example.com' and deletes them from the database.

The query builder can also be used to delete records:

$deleted = DB::table('users')->where('votes', '<&#39;, 100)->delete();

This code will delete all users with less than 100 votes from the database.

Summary

Laravel provides powerful addition, deletion, modification and query functions, allowing developers to easily access the database and perform operations. Thanks to Laravel's Eloquent ORM and query builder, we can easily create, read, update, and delete data. I believe that after mastering these basic knowledge of addition, deletion, modification and query, the work of Laravel developers will become more efficient and enjoyable.

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