diesel_returning_clause_sqlite335.md

How to use SQLite3.35+ and Diesel?

Sadly, the Diesel Sqlite3 examples do not contain any hint for the needed Diesel PR 3004. The PR adds a RUST Cargo feature for Diesel.

Despite the importance of the cargo feature returning_clauses_for_sqlite_3_35 it is not mentioned at all. The feature is required for the Diesel returning clause in the SQLite context of Diesel.

Put simply, SQLite 3.35 introduced the SQLite returning clause. The returning clause is used to get the new row/obj after a insert statement. Thus the missing returning clause affected Diesel until 2022. So until the PR and merge.

Example: How does the returning clause look like in Diesel?

  pub fn create_post(conn: &mut SqliteConnection, title: &str, body: &str, published: bool) -> Post
  {
  
      let new_post = NewPost { title, body, published };
  
      insert_into(posts)
          .values(&new_post)
          .returning(Post::as_returning()) // <-- that little part here is the returning clause(!)
          .get_result(conn)
          .expect("Error saving new post")
  }

Example: How does the cargo.toml look like?

diesel = {version="2.1.0", features = ["sqlite", "returning_clauses_for_sqlite_3_35"] }