PHP/MySQL how to insert and or update two MySQL tables?

Question

I was wondering how can I update my two database tables using PHP and MySQL? I want to add a second table called tags_2 that will check if a tag already exists and if it does add it to the current count in the table and if the tag does not exist add it to the table.

I hope I explained it right?

I basically need help in adding the correct code in the right places this has stumped me all day for some reason? I got the first table to work but not the second?

Here is my MySQL tables below.

CREATE TABLE tags (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
page TEXT NOT NULL,
tag VARCHAR(255) NOT NULL,
count INT NOT NULL,
PRIMARY KEY (id)
);

CREATE TABLE tags_2 (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
tag VARCHAR(255) NOT NULL,
count INT NOT NULL,
PRIMARY KEY (id)
);

And Here is my PHP script below.

<?php 

require_once ('./mysqli_connect.php');

if (isset($_POST['submitted'])){

  $mysqli = new mysqli("localhost", "root", "", "sitename");
  $dbc = mysqli_query($mysqli,"SELECT * FROM tags");
 if (!$dbc) {
  print mysqli_error($mysqli);
 }

$page = $_SERVER['SCRIPT_FILENAME'];

$tag = mysqli_real_escape_string($mysqli, $_POST['tag']);

$mysqli = new mysqli("localhost", "root", "", "sitename");
$dbc = mysqli_query($mysqli,"SELECT id, count, page FROM tags WHERE tag='$tag' AND page = '$page'");

if(mysqli_num_rows($dbc)){
  $tag_info = mysqli_fetch_array($dbc);
  $tag_info_id = $tag_info["id"];
  $tag_info_count = $tag_info["count"] + 1;

  $mysqli = new mysqli("localhost", "root", "", "sitename");
  $dbc = mysqli_query($mysqli,"UPDATE tags SET count='$tag_info_count' WHERE id='$tag_info_id'");

  echo "$tag now with $tag_info_count instances";
} else {
  $mysqli = new mysqli("localhost", "root", "", "sitename");
  $clean_url = mysqli_real_escape_string($mysqli, $page);
  $dbc = mysqli_query($mysqli,"INSERT INTO tags (tag, count, page) VALUES ('$tag', 1, '$clean_url')");

if (!$dbc) {
  print mysqli_error($mysqli);
}
echo "1 record added";
}
mysqli_close($mysqli);
}
?>

Will the tables look better like this.

CREATE TABLE tags (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
page TEXT NOT NULL,
tag VARCHAR(255) NOT NULL,
count INT NOT NULL,
PRIMARY KEY (id)
);

CREATE TABLE tags_2 (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
tag_id INT UNSIGNED NOT NULL DEFAULT 0, 
tag VARCHAR(255) NOT NULL,
count INT NOT NULL,
PRIMARY KEY (id)
);

Answer 1

First off, your schema isn't normalized. Put all the data about tags in one table. Put data about pages in another table. In the Pages table, include a foreign key that refers to the primary key of the tags table:

CREATE TABLE pages(
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
page TEXT NOT NULL,
tag_id INT UNSIGNED,
tag_count INT NOT NULL DEFAULT 0, //count is a reserved word
PRIMARY KEY (id),
FOREIGN KEY (tag_id) REFERENCES tags(id)
                      ON DELETE RESTRICT

);

CREATE TABLE tags (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
tag VARCHAR(255) NOT NULL,
PRIMARY KEY (id)
);

Then, in pseudocode, your queries become:

$var= SELECT id FROM tags WHERE tag='somestring';
if $var!=0 { 
  UPDATE pages SET tag_id=$var, 
                   tag_count=tag_count+1 
  WHERE page_id='a page id';
}