Uncaught PDOException: SQLSTATE[3D000]: Invalid catalog name: 1046 No database selected in E:\Work\Aptech\XAmpp\htdocs\myproject\rest\models\Post.php:45

[vuivehieu]

I'm having this trouble, any suggests?
Thank you for the codes

Post.php
`<?php
class Post{
//DB
private $conn;
private $table = 'posts';

//post properties
public $id;
public $category_id;
public $category_name;
public $title;
public $body;
public $author;
public $created_at;

//constructor
public function __construct($db)
{
	$this->conn = $db;
}
//get posts

public function read(){
	//creat query
	$query = 'SELECT 
	C.name as category_name,
    p.id,
    p.category_id,
    p.title,
    p.body,
    p.author,
    p.created_at    
    FROM
    ' .$this->table. ' p
    LEFT JOIN 
     categories c ON p.category_id = c.id
     ORDER BY 
     p.created_at DESC';


     //prepare statement
     $stmt = $this->conn->prepare($query);

     //execute
     $stmt->execute();

     return $stmt;
}

}`

Database.php
`<?php
/**
*
*/
class Database
{
private $host = 'localhost';
private $db_name = 'testt';
private $username = 'root';
private $password = '';
private $conn;

//DB connect
public function connect()
{
	$this->conn = null;

	try{
		$this->conn = new PDO('mysql:host='.$this->host.';dbname ='.$this->db_name,$this->username, $this->password);
		$this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

	}
	catch(PDOException $e){
		echo 'Connection Error: '.$e->getMessage();
	}
	return $this->conn;
}

}
?>`

read.php
`<?php
//Headers
header('Access-Control-Allow-Origin: *');
header('Content-Type:application/json');

include_once 'E:/Work/Aptech/XAmpp/htdocs/myproject/rest/Database.php';
include_once 'E:/Work/Aptech/XAmpp/htdocs/myproject/rest/models/Post.php';

//Install DB & connect
$database = new Database();
$db = $database->connect();

//Instantiate Post object
$post = new Post($db);

//Blog post query
$result = $post->read();
//Get row count
$num = $result->rowCount();

//check if any posts
if($num>0)
{
//post array
$posts_arr = array();
$posts_arr['data']=array();

while($row = $result->fetch(PDO::FETCH_ASSOC)){
	extract($row);

	$post_item = array(
    'id'=>$id,
    'title'=>$title,
    'body'=> html_entity_decode($body),
    'author'=>$author,
    'category_id'=>$category_id,
    'category_name'=> $category_name
	);

    //push to "data"
    array_push($posts_arr['data'], $post_item);
}

//turn to JSON &output
echo json_encode($posts_arr);

}else{
//no post
echo json_encode(
array('message'=>'No Posts Found')
);
}
`

[Omdal]

I had the same error. Removing a misplaced space worked for me:

Database.php in function connect:

try{
    $this->conn = new PDO('mysql:host='.$this->host.';dbname ='.$this->db_name,$this->username, $this->password);
                                       // Remove this space ^

the corrected line should be:
$this->conn = new PDO('mysql:host='.$this->host.';dbname='.$this->db_name,$this->username, $this->password);