Ok, after a whole day with this, I need some help. I am trying to bulk insert some values using next-jdb but I keep bumping into this error:

And here is my code:

(defn insert-multiple-design-versions!
  "Given an array of versions containing the
  :picture key as an array of uri's, extracts the
  pictures from every design-version constructs the
  insertable objects for versions and pictures and inserts them in the correct tables"
  [db versions]
  (let [db-pictures (into [] (flatten (map construct-db-pictures versions)))
        db-versions (into [] (map #(dissoc % :pictures) versions))]
    (jdbc/with-transaction
      [tx db]
      (sql/insert-multi! tx :design-version
                         [:design-id :version-id :name :description] db-versions)
      (sql/insert-multi! tx :picture
                         [:uri :version-id :picture-id]
                         db-pictures))))

The error throws at the first insert-multi , I assume it has something to do with sql types and I read the docs on next-jdbc/as-type part but I don’t know how to use it. An example data from db-versions is

{:description "Design option description"
 :name        "Design option 2"
 :design-id   "9cd035eb-a4d0-4ce2-ae75-b3b3cdcb76ed"
 :version-id  "4e901694-4279-4722-bfea-8fd841f772aa"}

Also, I am a beginner with clojure so any feedback on my code is greatly apreciated 😄

What are you passing in as versions?

The error suggests you are passing MapEntry values so I suspect you are passing a hash map where a sequence of hash maps is expected @ovidiu.stoica1094

hmmm

So you mean I am passing a map instead of an array

That does make sense. Let me debug a bit with this in mind

insert-multi! expects a connection, a table, a list of column names and list of row values -- a list of lists (or a vector of vectors). (into [] (flatten ..)) is going to produce a single long sequence instead of a sequence of sequences so that's def. going to fail for the second insert (of db-pictures).

It looks like versions is a sequence of hash maps so db-versions will also be a sequence of hash maps, so that is also not acceptable to insert-multi!

Omg

Yes I was passing a list of maps with key-value pairs instead of a list of lists with only the values

juxt would be very helpful here: (juxt :design-id :version-id :name :description) produces a function that, when applied to a hash map, will pull out those values in the specified order (hash maps are inherently unordered).

So I think you want (map (juxt :the :keys :you :want) list-of-hash-maps)

I was actually looking for something exactly like that earlier 😮

flatten is almost never the right answer to any problem 🙂

🙂

I’ll make sure to remember 😄

Thank you so much, @seancorfield and also, since I have a chance to talk to you, thank you so much for next.jdbc . It has been a great help for me and I’m definitely learning a lot from how you wrote the code in the lib. I’m browsing through it from time to time

I'd probably do something like this:

(let [pic-cols [:design-id :version-id :name :description]
  (sql/insert-multi! ds :design-version pic-cols (map (apply juxt pic-cols) pictures)))

(off the top of my head)

That is great. Easy to understand