How to add new column to existing table without losing data in Laravel

Laravel

In Laravel we will learn how to add new column to existing table without losing data by using migration.   Lets us see an example , we are going to create a migration for blogs. <ol> <li> If you don’t know how to create migration then you can see below command otherwise leave it, and move to second point. </li> </ol>   Syntax <pre><code> php artisan make:migration create_tablename_table</code></pre>  Example  We will follow the syntax and create migration for blog, after created migration you can see the table. In this table there are two function<code>up()</code>  for run the migration table and <code>down()</code> for reverse migration. Now run the below command. <pre><code>    Php artisan make:migration create_blogs_table</code></pre> After migration you can add table field name, we are adding one field that is <code>“title”.</code> <pre><code>/** Run the migrations */ public function up(): void { Schema::create('blogs', function (Blueprint $table) { $table->id(); $table->string('title'); $table->timestamps(); }); } /** Reverse the migrations. */ public function down(): void { Schema::dropIfExists('blogs'); }</code></pre> Now run command <code>php artisan migrate</code> and see your table in MySQL database. <ol start="2"> <li> Now we want to add new column “slug” in blogs existing table without losing data. </li> </ol> So we have to create another migration for add new column , you can put any name as per your choice so we are creating migrate with <code>“alter_blog_table” </code>name. <pre><code>php artisan make:migration create_alter_blogs_table</code></pre> now you can see your migrated schema blow code in this, we have to add new field “slug” in both <code>up()</code> and <code>down() </code>function and run  artisan <pre><code>   public function up(): void      { /** here you have add schema with previous table name, in previous table blogs is the table name. */      Schema::table('blogs', function (Blueprint $table) {           $table->string('slug'); // add new column HERE     });   }    /** Reverse the migrations. */     public function down(): void      {           Schema::table('blogs', function (Blueprint $table) {                $table->dropColumn('slug');  // Here you have to add field           });      }</code></pre> Now you can see again blogs table in your database, new field added successfully without losing data in Laravel.

Laravel

Laravel Eloquent display query log in php

Laravel

In this article we will learn about log query in Laravel.  It helps us to view the query of laravel application. Sometime we want  to display last executed query in laravel application for debug. While working with project then sometime we need to display some log query  so that we need to check the query is correct or not . it reduces our time while debugging the code. Lets see the following example of eloquent query in laravel. <ol class="listc"> <li>toSql()</li> <li>DB::enableQueryLog()</li> <li>DB::getQueryLog()</li> </ol> <ol> <li> <h2 class="ht2">toSql() : </h2> </li> </ol> We will see the example of toSql() query . while we working with database query then we need to see the query that is correct or not that why we should use toSql(). Example 1 ( Controller Code ) <pre><code>$query = User::select("*")->toSql();                                                                                                                                                                                     dd($query);</code></pre> Output <pre>select * from `users`</pre> <ol start="2"> <li> <h2 class="ht2">DB::enableQueryLog()</h2> </li> </ol> While working with DB query builder the we should use this db enable query. we have to use this package <code>"use Illuminate\Support\Facades\DB"</code> Example 2. (controller Code) <pre><code>use Illuminate\Support\Facades\DB;”  ... ... public function show(){       DB::enableQueryLog();       $arr_user = DB::table('users')->select('name', 'email as user_email')->get();      // same will work for Eloquent      // $user = User::find(1);        dd(DB::getQueryLog()); }</code></pre> Output <pre>array:1 [▼ // app/Http/Controllers/Api/ContactController.php:28   0 => array:3 [▼ "query" => "select `name`, `email` as `user_email` from `users`"     "bindings" => []     "time" => 11.0     ] ] </pre> Example 2 ( Controller code ) <pre><code>DB::enableQueryLog(); $users = User::select("*")->get(); $quries = DB::getQueryLog(); dd($quries);</code></pre> Output <pre>array:1 [▼      0 => array:3 [▼      "query" => "select * from `users`"      "bindings" => []      "time" => 4.25     ] ]</pre> <ol start="3"> <li> <h2 class="ht2">DB::getQueryLog()</h2> </li> </ol> This is the another example of query builder in laravel in which we can use “DB::getQueryLog()” to get query. It will execute in short time in compression toDB::enableQueryLog(); <pre><code>    DB::enableQueryLog();         $users = User::select("*")->get();         $query = DB::getQueryLog();        $query =end($query);        dd($query);</code></pre> Output  <pre>array:3 [▼    "query" => "select * from `users`"     "bindings" => []     "time" => 2.07    ] </pre> Thank you reading this article , Hope it will helpful to you ..!

Laravel

What is traits in PHP with example

Laravel

In Laravel we will learn about Traits and how to upload image in folder using traits. What are Traits? PHP only support single inheritance (a child class can inherit only from one single parent). But if we want to use multi-inheritance (if a class needs to inherit multiple behaviours) then PHP OOP Traits solve this problem. Traits is used to declare methods that can be used in multiple classes, and it can have methods and abstract methods that can be used in multiple classes, and the methods can have any access modifier (public, private, or protected). Note: We can declare Traits with the <code>trait </code>keyword. Here a small example of trails just for understand. We will learn more to next point. Example. <pre><code><?php trait class1 {      public function msg1() {            echo "OOP is fun! ";       }   } Class class2 {    use class1; } $obj = new class2(); $obj->msg1(); ?></code></pre> <h2>How to upload image in Laravel using Traits</h2> In Laravel we will upload image in public folder using traits, so there are given few step we should follow: <ol> <li>First Create trait folder inside the app folder. We can create Traits file <code>“saveFile.php”</code> inside <code>“App\Traits”</code> folder and follow the below code.</li> </ol> <pre><code><?php namespace App\traits; trait saveFile{        protected function saveImage($file){                $image_name= time().'.'.$file->extension(); // get image name                $file->move(public_path('images/'), $image_name); // move image to public image folder                return $image_name;          }  }</code></pre> <ol start="2"> <li> Now create Blade file as per your choice We are going to create blade <code>“blog.balde.php”</code> file inside views folder and create form for upload image. In form action <code>“saveImageTrait”</code> route we will create next part. </li> </ol> <pre><code><div class="container"> <h2>Upload Image Via Traits</h2>      <label for="email">Image Upload</label> <form action="{{url('saveImageTrait')}}" method="post" enctype="multipart/form-data"> @csrf <div class="form-group"> <input type="file" class="form-control" name="image"> </div> <button type="submit" class="btn btn-default">Submit</button> </form> </div> </code></pre> <ol start="3"> <li>Create Controller and call traits. Now we will create a controller and call traits function , you can create controller using given below command.</li> </ol> <pre><code>php artisan make:controller BlogController</code></pre> Now put the given code into it <pre><code><?php namespace App\Http\Controllers; use App\Models\blogs; // add Model use Illuminate\Http\Request; use App\Traits\saveFile; // Declare traits class BlogsController extends Controller {  use  saveFile;  // use traits    public function saveImageTrait(Request $request){       /* saveImage() call from traits class */        $imageName=$this->saveImage($request->image);        print($imageName); /* You can write code for save the image name  */     }    // For call blade file upload image    public function index(){        return view('blog');     } } </code></pre> <ol start="4"> <li>Now create Route We can create route for call blade file form and save image to folder follow then give code.</li> </ol> <pre><code> <?php use Illuminate\Support\Facades\Route; use App\Http\Controllers\BlogsController; # call blade file Route::get('blogs', [BlogsController::class, 'index']); # save image to folder Route::post('saveImageTrait',[BlogsController::class, 'saveImageTrait']);</code></pre> Now you can see image in <code>"public/image"</code> folder

Laravel

What is Query Builder and Eloquent in Laravel

Laravel

Query Builder and Eloquent in Laravel The Query Builder and Eloquent  is most important part of Laravel. We can perform various types of database tables operations ( crud ). Laravel provide two ways to perform these.   <ol> <li>Query Builder</li> <li>Eloquent ORM ( Object Relationship Model)</li> </ol>  1. Query Builder Laravel's database query builder provides a convenient, fluent interface to creating and running database queries. It is used to perform database operations in your application and works perfectly with all of Laravel's supported database systems. Database tables are often related to another table. Before starting a relationship topic, Features of Query Builder    a) It interacts with multiple databases like, SQLlite, Mysql, Postgresql etc.    b) It protects the application against SQL injection attacks because it supports PDO ( PHP Data Objects ).    c) We can write SQL queries in the controller we can see the example below.  Example1 <div> <pre><code><?php namespace App\Http\Controllers; use App\Models\Student; use Illuminate\Http\Request; use Illuminate\Support\Facades\DB; class StudentController extends Controller{ publicfunction index(){       $data= DB::table('students')->get();       dd($data);    } } ?></code></pre> Output Student Records Here we have to write <code>"use Illuminate\Support\Facades\DB;</code>" after namespace in top section. After that we can write query..</div> 2. Eloquent ORM The Eloquent ORM stands for an object relation mapper and it is a technique to access objects without having to consider how those objects are related to their source. , it is by default built in Laravel. It is used to handle database records by data as objects.  The Eloquent ORM included with Laravel provides a beautiful, simple ActiveRecord implementation for working with your database. Each database table has a corresponding "Model" used to interact with that table. When we use Eloquent, each database table has a corresponding "Model" used to interact with that table. In addition to retrieving records from the database table, Eloquent models allow you to insert, update, and delete records from the table as well. Relationships Laravel In Laravel relationships are defined as methods on your Eloquent model classes. Since relationships also provide powerful “query builders”, it is used to define the relationships as the method provides powerful method chaining and querying capabilities.   In Laravel Eloquent makes managing and working with these relationships easy. but, before diving too deep into using Laravel relationships, let's learn how to define each type of relationship supported by Eloquent. It provides various types of  common relationships: Types of Relationship <ol> <li>One To One</li> <li>One To Many</li> <li>Many To Many</li> <li>Has One Through</li> <li>Has Many Through</li> <li>One To One (Polymorphic)</li> <li>One To Many (Polymorphic)</li> <li>Many To Many (Polymorphic)</li> </ol> In the given above relationship we will learn not all but basics we will cover for those who started learning relationships in Laravel. <ol> <li>One To One In Laravel one to one relationship is a basic database relationship, it means a relationship between two tables.  we will retrieve the single records. In one to one relationship we will use the hasOne() method that returns the result.The hasOne() method is available in our model via the model's “Illuminate\Database\Eloquent\Model base” class.</li> </ol> Example of one to one relationship in Laravel In this example, we will create two tables “Company” and “Member” and make a relation using foreign key and another way also. We will follow the given steps: <ol> <li>Create two model, controllers and migration. <code>php artisan make:model Student -crm;</code> <code>php artisan make:model Training -crm;</code></li> <li>Open the migration file and put the below code</li> <li>Student Table</li> </ol> <pre><code>     public function up(){         Schema::create('students', function (Blueprint $table) {               $table->id();               $table->string("name");               $table->string("mobile");               $table->timestamps();        });      }</code></pre> <ol> <li>Training Table</li> </ol> <pre><code>public function up(){    Schema::create('trainings', function (Blueprint $table) {         $table->id();         $table->string('name');         $table->timestamps();         $table->foreignId('student_id');     }); }</code></pre> <ol> <li>Now run migrate command.</li> </ol> <code>     Php artisan migrate</code> <ol> <li>Now Open Students model and put in the following code</li> </ol> <pre><code><?php namespace App\Models; use Illuminate\Database\Eloquent\Factories\HasFactory; use Illuminate\Database\Eloquent\Model; class Student extends Model{   use HasFactory;   public function Training(){ return $this->hasOne(Training::class);    } }</code></pre> <ol> <li>Now Open the Trainings model and put in the following code.</li> </ol> <pre><code><?php namespace App\Models; use App\Models\Training; use Illuminate\Database\Eloquent\Factories\HasFactory; use Illuminate\Database\Eloquent\Model; class Training extends Model{    use HasFactory; }</code></pre> <ol> <li>Now open Student Controller and add Training</li> </ol> <pre><code><?php namespace App\Http\Controllers; use App\Models\Student; use App\Models\Training; use Illuminate\Http\Request; class StudentController extends Controller{ public function index(){       $data= Student::with('Training')->get();         return $data;     } } </code></pre> Here we have used with() function and we will call Student model function which is “Training”. You can check in student model. <ol> <li>Now create Route:</li> </ol>  <code>     Route::get('students',[StudentController::class,'index']);</code> <ol> <li>Open Web Url and check the outputs</li> </ol> Output   <ol start="2"> <li>One To Many</li> <li>Many To Many</li> </ol> Ref: if we want to know more about Relationship in Laravel  <a href="https://laravel.com/docs/10.x/eloquent-relationships#introduction">Click here</a> for official Website of Laravel.

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How to add new column to existing table without losing data in Laravel

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