Question

I’m having some problems with the code below. What I’m trying to do is to tell if a tag already exists in the table tags, if it does, get the id and put that id in the table blog_post_tags, or if it does not exist, create it, get the id and put it in blog_post_tags table. The problem is that, whenever I try to check if the id already exists, I get errors all over the place telling me trying to get property of non object but fields are still being insert in the other table with an id of 0 (which is not a valid id for the tags).

Here is the code:

foreach ($tags as $tag)
{
    //search for the tag to see if it exists 
    //the problem is located in this line of code
    if($select_stmt = $mysqli->prepare("SELECT id FROM tags WHERE name = ?"))
    {
        $select_stmt->bind_param("s",$tag);
        $select_stmt->execute();
        $result = $select_stmt->get_result();

        //if the tag exists
        if($select_stmt->num_rows != 0)
        {
            if($insert_stmt = $mysqli->prepare("INSERT INTO blog_post_tags (blog_post_id, tag_id) VALUES (?,?)"))
            {
                $insert_stmt->bind_param('ii', $blogid, $result);
                $insert_stmt->execute();
            }
        }
        else
        {
            if ($insert_stmt2 = $mysqli->prepare("INSERT INTO tags (name) VALUES (?)")) 
            {
                $insert_stmt2->bind_param('s', $tag);
                $insert_stmt2->execute();
                $tagid = $mysqli->insert_id;

                if ($insert_stmt3 = $mysqli->prepare("INSERT INTO blog_post_tags (blog_post_id, tag_id) VALUES (?, ?)"))
                {
                    $insert_stmt3->bind_param('ii', $blogid, $tagid);
                    $insert_stmt3->execute();
                }
            }
        }
    }
}

Thanks in advance for the help.

EDIT

Some how, the “trying to get property of a non object” disappeared, i suspect it may have been a connection erro with the server but i really cant tell, still the table blog_post_tags is being filled with fields that does not make any sense, “tag_id =0”. i suspect it may have something to do with the problem expressed here: php prepared stmt problem- update data at each result loop
¿ how could i correct me code if the problem is related to that of the link above ?

Answer 1

Well, i really dont know what it did, but it seem to have worked, here is the code without any errors:

foreach ($tags as $tag)
        {
            //search for the tag to see if it exists
            if ($select_stmt = $mysqli->prepare("SELECT id FROM tags WHERE name = ?")) 
            {

                $select_stmt->bind_param("s", $tag);
                $select_stmt->execute();
                $select_stmt->store_result();

                if ($select_stmt->num_rows() > 0) 
                {

                    $select_stmt->bind_result($tagid);
                    $select_stmt->fetch();
                    if ($insert_stmt = $mysqli->prepare("INSERT INTO blog_post_tags (blog_post_id, tag_id) VALUES (?, ?)"))
                    {
                        $insert_stmt->bind_param('ii', $blogid, $tagid);
                        $insert_stmt->execute();
                    }
                }
                else
                {
                    if ($insert_stmt2 = $mysqli->prepare("INSERT INTO tags (name) VALUES (?)"))
                    {
                        $insert_stmt2->bind_param('s', $tag);
                        $insert_stmt2->execute();
                        $tagid = $mysqli->insert_id;

                        if ($insert_stmt3 = $mysqli->prepare("INSERT INTO blog_post_tags (blog_post_id, tag_id) VALUES (?, ?)"))
                        {
                            $insert_stmt3->bind_param('ii', $blogid, $tagid);
                            $insert_stmt3->execute();
                        }
                    }
                }
            }
         }

hopefully this can help anyone that encounters a similar problem, also, i would like to know if this solution is optimal or if there is any way to improve it.