php - SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails -

i know common problem don't know what's wrong here. can see there's //return $user , shows valid id. checked in database well.

        $user = new user;         $user->first_name           = $data['first_name'];         $user->last_name            = $data['last_name'];         $user->email                = $data['email'];         $user->phone_no             = $data['phone_no'];         $user->created_from         = 'web app';         $user->save();         // return $user;         session::put('user_id',$user->id);         // return $user->id;         $address = new address;         $address->user_id           = $user->id;         $address->first_name        = $data['receiver_first_name'];         $address->last_name         = $data['receiver_last_name'];         $address->email             = $data['receiver_email'];         $address->address_line_1    = $data['receiver_address_line_1'];         $address->address_line_2    = $data['receiver_address_line_2'];         $address->landmark          = $data['receiver_landmark'];         $address->pincode           = $data['receiver_pincode'];         $address->phone_no          = $data['receiver_phone_no'];         $address->created_from      = 'web app';         $address->save(); 

here migrations: users migration

<?php  use illuminate\database\schema\blueprint; use illuminate\database\migrations\migration;  class createuserstable extends migration {  /**  * run migrations.  *  * @return void  */ public function up() {     schema::create('users', function($table){         $table->increments('id');         $table->string('first_name');         $table->string('last_name');         $table->string('email');         $table->string('phone_no', 20)->nullable();         $table->string('password')->nullable();         $table->string('remember_token', 100);         $table->date('date_of_birth')->nullable();         $table->string('created_from');          $table->timestamps();         $table->softdeletes();     }); }  /**  * reverse migrations.  *  * @return void  */ public function down() {     schema::dropifexists('users'); } 

}

addresses

public function up() {     schema::create('addresses', function($table){         $table->increments('id');         $table->integer('user_id')->unsigned();         $table->string('first_name');         $table->string('last_name');         $table->string('email');         $table->string('address_line_1');         $table->string('address_line_2')->nullable();         $table->string('landmark')->nullable();         $table->string('city')->nullable();         $table->string('state')->nullable();         $table->string('phone_no', 13);         $table->integer('pincode');         $table->string('created_from');          $table->timestamps();         $table->softdeletes();          $table->foreign('user_id')->references('id')->on('users');     }); } 

here's screenshot of error if helps.

according error message, error caused inserting value in adresses.user_id (fk src.id), not exist in src.id.
in example, try insert 29 in adresses.user_id, check if select id src id=29 returns result. if not, there problem.