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

Laravel is a web application development framework based on PHP. Its powerful and flexible features are increasingly sought after by developers. When using Laravel to develop projects, it is a very common requirement to perform CRUD operations on the database. This article will introduce how to use Laravel to add, delete, modify and query database tables.

1. Connect to the database

In Laravel, connecting to the database requires modifying the .env file. In this file, we can define the database connection method, user name, password, database name and other information. The following is an example of a .env file:

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=laravel
DB_USERNAME=root
DB_PASSWORD=

Among them, DB_CONNECTION represents the database type used, which can be mysql, sqlite, pgsql, etc. DB_HOST represents the host address of the database, DB_PORT represents the port number of the database, DB_DATABASE represents the name of the database, DB_USERNAME represents the user who connects to the database Name, DB_PASSWORD represents the password to connect to the database.

2. Create a data table

In Laravel, you can use the artisan make:model command to create a model corresponding to the database table. Before generating the model file, we need to define the structure of the database table. In Laravel, you can use migration files to define the database table structure.

In the root directory of the Laravel project, use the following command to create a migration file named create_users_table:

php artisan make:migration create_users_table --create=users

where create_users_table is the migration file The name, --create=users means that we want to create a data table named users.

Modify the generated migration file and define the database table structure in the up method. For example, if we want to create a table named users, containing three fields: name, email and password, then we can do it as follows Define in the following way:

public function up()
{
    Schema::create('users', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->string('email')->unique();
        $table->string('password');
        $table->timestamps();
    });
}

After defining the migration file, execute the following command to apply the migration file to the database:

php artisan migrate

After successful execution, you can see the newly created Data sheet.

3. Add data

In Laravel, you can add, delete, modify and query database tables through the Eloquent model. In the previous step, we have created the User model. You can create a new user in the following way:

$user = new User;
$user->name = 'john';
$user->email = 'john@example.com';
$user->password = Hash::make('password');
$user->save();

First create a new User model object , then set the attributes of the model (that is, the fields of the data table), and finally call the save method to save the data to the database.

In addition, you can also use the create method to create and save model instances at one time:

$user = User::create([
    'name' => 'jane',
    'email' => 'jane@example.com',
    'password' => Hash::make('password')
]);

4. Query data

In Laravel, you can Use the Eloquent model to perform query operations on database tables. The following are some common query methods:

1. Get all model instances (that is, all records in the data table):

$users = User::all();

2. Get model instances based on the primary key:

$user = User::find(1);

3. Query model instances based on specified conditions:

$users = User::where('name', 'john')->get();

4. Use advanced query methods:

$users = User::where('name', 'like', 'j%')
             ->orderBy('name', 'desc')
             ->take(10)
             ->get();

In use When using advanced query methods, multiple query conditions can be chained to filter out model instances that meet the requirements.

5. Modify data

In Laravel, you can update the data in the database table by modifying the attributes of the model instance. For example, to change the email address of the user record name to john to john@example.org, you can proceed as follows:

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

Or use the update method to perform batch update operations:

User::where('name', 'john')->update(['email' => 'john@example.org']);

6. Delete data

In Laravel, you can use the Eloquent model to do it Database table deletion operation. To delete a specified model instance, you can use the following method:

$user = User::find(1);
$user->delete();

or use the destroy method to delete multiple model instances in batches:

User::where('name', 'john')->delete();

The above is using Laravel for database Basic knowledge of table addition, deletion, modification and query operations. Laravel has powerful ORM functions that can help developers perform database operations more efficiently.

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