OCAML SQLite3 预准备语句-解网

问：

我在 ocaml 中有以下 sqlite3 插入，效果正常。

type article = { author : string; content: string }

let insert_article db (article: article) =
  let sql = Printf.sprintf "INSERT INTO blog (author, content) VALUES ('%s', '%s')" article.author article.content in
  match exec db sql with
  | Rc.OK -> ()
  | _ -> raise @@ Error "Failed to insert"

如何将其转换为使用预准备语句？

我尝试过这种事情，但是没有用于作者和内容参数的插槽，

let insert_article db (article: article) =
  let sql = prepare db "INSERT INTO blog (author, content) VALUES (?, ?)" article.author article.content in
  match exec db sql with
  | Rc.OK -> ()
  | _ -> raise @@ Error "Failed to insert"

我在这里对 API 类型文档没有多大意义：http://mmottl.github.io/sqlite3-ocaml/api/sqlite3/Sqlite3/index.html#prepared-statements

我是 OCaml 的新手，有点困惑。任何指导将不胜感激。

sqlite ocaml 准备语句

let insert_article db (article : article) =
  let stmt = prepare db "INSERT INTO blog (author, content) VALUES (?, ?)" in
  let authorBind = bind stmt 1 @@ Data.TEXT article.author in
  let contentBind = bind stmt 2 @@ Data.TEXT article.content in
  match (authorBind, contentBind) with
  | Rc.OK, Rc.OK -> (
      match step stmt with 
      | Rc.DONE -> () 
      | _ -> failwith "Failed to insert"
    )
  | _ -> failwith "Failed to bind parameters to the SQL query"

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下一个：我创建了一个 PreparedStatement 对象，当我检查该元素时，我可以看到 m_type=12。这是什么m_type=12

OCAML SQLite3 预准备语句

ocaml sqlite3 prepared statement

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