Create posts in WordPress from data in a MySQL database. Full article at: http://imelgrat.me/wordpress/bulk-upload-custom-posts-wordpress/

bulk-post-create.php

<?php
  	// Create posts in WordPress from data in a MySQL database. Full article at: http://imelgrat.me/wordpress/bulk-upload-custom-posts-wordpress/
        //Load WordPress functions and plug-ins. Put correct path for this file. This example assumes you're using it from a sub-folder of  WordPress
	require_once ('../wp-load.php'); 

	$database['hostname'] = 'SERVER';
	$database['username'] = 'USER';
	$database['password'] = 'PASSWORD';
	$database['database'] = 'DATABASE';

	$mysql_link = mysqli_connect($database['hostname'], $database['username'], $database['password']);
	mysqli_select_db($mysql_link, $database['database']);
	mysqli_query($mysql_link, "SET NAMES UTF8");
	mysqli_query($mysql_link, "SET NAMES 'UTF8'");
	mysqli_query($mysql_link, "SET CHARACTER SET UTF8");

/*
--
-- Table structure for table `products`
--
  CREATE TABLE IF NOT EXISTS `products` (
    `product_id` bigint(20) NOT NULL AUTO_INCREMENT,
    `name` varchar(255) NOT NULL,
    `description` text NOT NULL,
    `price` float NOT NULL,
    `ingredients` text NOT NULL,
    PRIMARY KEY (`product_id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
*/
	$query = "SELECT * FROM `products` WHERE `proccessed`= 0 ORDER BY `products`.`id` ASC;"; // products 
	$result = mysqli_query($mysql_link, $query);

	while ($row = mysqli_fetch_assoc($result))
	{
		// Insert the post and set the category. See https://gist.github.com/imelgrat/46da054bc27d10dbdff5408502623b2d for custom post type declaration
		$post_id = wp_insert_post(array(
			'post_type' => 'product',
			'post_title' => $row['name'],
			'post_content' => $row['description'],
			'post_status' => 'publish', // Can be draft, pending or any other post status
			'comment_status' => 'closed', // if you prefer
			'ping_status' => 'closed', // if you prefer
			));

		if ($post_id)
		{
			// Insert post meta (ACF Custom Fields)
			add_post_meta($post_id, 'price', $row['price']);
			add_post_meta($post_id, 'ingredients', $row['ingredients']);
		}

    echo $row['name'].' posted<br>';
	}
?>

It says "Insert the post and set the category" but it doesn't set the category, is it needed or not?