从INSERT IGNORE语句获取多个插入ID

Question

I want to realize a tag feature for article posts, so a user can add several tags when posting an article.

I have a tags table, an articles table and a article_tags table.

tags:

id | tag (Unique)

articles:

id | title | content

article_tags:

id | article_id | tag_id

So (1) when a new article is to insert, I need to insert into the articles table and get the insert id as article_id .

(2) Then, I use a single INSERT IGNORE statement to insert multiple tags into the tags table. Among these tags, some may exists and will be ignored.

(3) Now I am about to insert the relations of articles and tags with article_tags . However, how can I get the IDs in step (2) to serve as tag_id in the last table?

Or I just cannot (instead, to use a one by one insert solution)?

Answer 1

@AdrienXL's answer is a one-by-one solution.

I find that I can first batch insert the tags with INSERT IGNORE .

And when I insert the relations for article_tags , I can use a "batch select" query to get the IDs. So I don't necessarily need to manually fetch and store the tags' IDs in tags table.

The pseudo-SQLs would like:

INSERT IGNORE tags (tag) VALUES [the tag array]

And

INSERT INTO article_tags (tag_id, article_id) 
    SELECT id, [some_article_id] FROM tags WHERE tag IN [the tag array]

Answer 2

Model :

   public function insert_articles($data)
   {
      $this->db->insert('articles', $data);
      return $this->db->insert_id(); 
   }

   public function insert_tags($data)
   {
     $insert_query = $this->db->insert_string('tags', $data);
     $insert_query = str_replace('INSERT INTO','INSERT IGNORE INTO',$insert_query);
     $this->db->query($insert_query);

     return $this->db->insert_id(); 
   }

   public function insert_article_tags($data)
   {
     return $this->db->insert_batch('articles_tags', $data);
   }

Controller :

   public function myfunction()
   {
     $id_article = $this->my_model->insert_articles($data);
     $article_tags = array();
     foreach($mytags as $t)
     {
         $id_tag = $this->my_model->insert_articles($data);
         array_push($article_tags, array("id_article" => $id_article, "id_tag" => $id_tag));
         //Supposed two fields table : id_article | id_tag
     }

     $this->my_model->insert_article_tags($data);
   }