Use ON CONFLICT upsert for genres

Replace the previous IF EXISTS/UPDATE/INSERT logic in the update_genre
PL/pgSQL function with a single INSERT ... ON CONFLICT DO UPDATE to
perform an atomic upsert and avoid races. Reformat the client.execute
call for readability.

.gitignore

@@ -1,2 +1,3 @@
 /target
-.vscode
+/.vscode
+/bruno

src/types.rs

@@ -828,30 +828,28 @@ impl FromVecExpression<Genre> for Genre {
 #[async_trait]
 impl Update for Genre {
     async fn before_update(client: &Client) -> Result<(), Box<tokio_postgres::Error>> {
-        match client.execute(
+        match client
-            "
+            .execute(
-            CREATE OR REPLACE FUNCTION update_book_sequence(source_ smallint, book_ integer, genre_ integer) RETURNS void AS $$
+                "
-                DECLARE
+            CREATE OR REPLACE FUNCTION update_genre(
-                    book_id integer := -1;
+                source_ smallint, remote_id_ int, code_ varchar, description_ varchar, meta_ varchar
-                    genre_id integer := -1;
+            ) RETURNS void AS $$
                 BEGIN
-                    SELECT id INTO book_id FROM books WHERE source = source_ AND remote_id = book_;
+                    INSERT INTO genres (source, remote_id, code, description, meta)
-
+                        VALUES (source_, remote_id_, code_, description_, meta_)
-                    IF book_id IS NULL THEN
+                    ON CONFLICT (source, remote_id) DO UPDATE SET
-                        RETURN;
+                        code = EXCLUDED.code,
-                    END IF;
+                        description = EXCLUDED.description,
-
+                        meta = EXCLUDED.meta;
-                    SELECT id INTO genre_id FROM genres WHERE source = source_ AND remote_id = genre_;
-                    IF EXISTS (SELECT * FROM book_genres WHERE book = book_id AND genre = genre_id) THEN
-                        RETURN;
-                    END IF;
-                    INSERT INTO book_genres (book, genre) VALUES (book_id, genre_id);
                 END;
             $$ LANGUAGE plpgsql;
-            "
+            ",
-            , &[]).await {
+                &[],
-                Ok(_) => Ok(()),
+            )
-                Err(err) => Err(Box::new(err)),
+            .await
+        {
+            Ok(_) => Ok(()),
+            Err(err) => Err(Box::new(err)),
         }
     }