I have a table of users, a table of hashtags, and a table linking the users to hashtags, like so:

Table users {
  id,
  name
}

Table hashtags {
  id,
  value
}

Table user_hashtags {
  id,
  user_id,
  hashtag_id
}

Whenever a user makes a post using several hash tags, I want to:

1. Create a new row in users if needed and get the ID
2. Create new rows in hashtags for hashtags that don’t exist and get their IDs
3. For each hashtag, create a row in user_hashtags with the user and hashtag ids

Right now I’m capable of handling it on the server side but obviously that’s terrible performance; for each hashtag, insert into hashtags if it doesn’t exist and get the ID; then insert into the user_hashtags. Lots of calls to DB that I’m guessing could be simplified, but my SQL skills are lacking at the moment. I’m not even quite sure how t