Expose sqlstate in the connection and stmt APIs.

bindings/ffi_bindings.ml

@@ -305,6 +305,9 @@ module Bindings (F : Cstubs.FOREIGN) = struct
   let mysql_ping = foreign "mysql_ping"
     (mysql @-> returning int)
 
+  let mysql_sqlstate = foreign "mysql_sqlstate"
+    (mysql @-> returning string)
+
   let mysql_stmt_prepare = foreign "mysql_stmt_prepare"
     (stmt @-> ptr char @-> ulong @-> returning int)
 
@@ -317,6 +320,9 @@ module Bindings (F : Cstubs.FOREIGN) = struct
   let mysql_stmt_fetch = foreign "mysql_stmt_fetch"
     (stmt @-> returning int)
 
+  let mysql_stmt_sqlstate = foreign "mysql_stmt_sqlstate"
+    (stmt @-> returning string)
+
   let mysql_stmt_close = foreign "mysql_stmt_close"
     (stmt @-> returning my_bool)
 

examples/blocking/blocking_example.ml

@@ -48,6 +48,37 @@ let stream res =
   try Ok (Stream.from next)
   with F.E e -> Error e
 
+let test_sqlstate mariadb =
+  assert (M.sqlstate mariadb = "00000");
+  (match M.prepare mariadb "SELECT * FROM inexistent_table" with
+   | Error _ -> assert (M.sqlstate mariadb <> "00000") (* actually "42S02" *)
+   | Ok _ -> assert false);
+  begin
+    let stmt =
+      M.prepare mariadb
+                "CREATE TEMPORARY TABLE test_sqlstate (i integer PRIMARY KEY)"
+        |> or_die "prepare CREATE TABLE test_sqlstate"
+    in
+    let _ =
+      M.Stmt.execute stmt [||]
+        |> or_die "exec CREATE TABLE test_sqlstate"
+    in
+    M.Stmt.close stmt |> or_die "stmt close CREATE TABLE test_sqlstate"
+  end;
+  for i = 0 to 1 do
+    let stmt =
+      M.prepare mariadb "INSERT INTO test_sqlstate VALUES (?)"
+        |> or_die "prepare in test_sqlstate"
+    in
+    (match M.Stmt.execute stmt [|`Int 1|] with
+     | Error (_, msg) ->
+        assert (i = 1);
+        assert (M.Stmt.sqlstate stmt <> "00000") (* actually "23000" *)
+     | Ok _ -> assert (i = 0));
+
+    M.Stmt.close stmt |> or_die "stmt close in test_sqlstate"
+  done
+
 let main () =
   let mariadb = connect () |> or_die "connect" in
   let query = env "OCAML_MARIADB_QUERY"
@@ -59,6 +90,7 @@ let main () =
   let s = stream res |> or_die "stream" in
   Stream.iter print_row s;
   M.Stmt.close stmt |> or_die "stmt close";
+  test_sqlstate mariadb;
   M.close mariadb;
   M.library_end ();
   printf "done\n%!"

lib/blocking.ml

@@ -152,6 +152,8 @@ let prepare mariadb query =
   | Some raw -> build_stmt raw
   | None -> Error (2008, "out of memory")
 
+let sqlstate = Common.sqlstate
+
 module Res = struct
   type t = [`Blocking] Common.Res.t
 
@@ -198,6 +200,8 @@ module Stmt = struct
     else
       Error (Common.Stmt.error stmt)
 
+  let sqlstate = Common.Stmt.sqlstate
+
   let close stmt =
     let raw = stmt.Common.Stmt.raw in
     if B.mysql_stmt_free_result raw && B.mysql_stmt_close raw then

lib/common.ml

@@ -85,6 +85,9 @@ type error = int * string
 let error mariadb =
   (B.mysql_errno mariadb.raw, B.mysql_error mariadb.raw)
 
+let sqlstate mariadb =
+  B.mysql_sqlstate mariadb.raw
+
 let int_of_server_option = function
   | Multi_statements true -> T.Server_options.multi_statements_on
   | Multi_statements false -> T.Server_options.multi_statements_off
@@ -280,6 +283,9 @@ module Stmt = struct
   let error stmt =
     (B.mysql_stmt_errno stmt.raw, B.mysql_stmt_error stmt.raw)
 
+  let sqlstate stmt =
+    B.mysql_stmt_sqlstate stmt.raw
+
   let fetch_field res i =
     coerce (ptr void) (ptr T.Field.t) (B.mysql_fetch_field_direct res i)
 

lib/mariadb.ml

@@ -79,6 +79,7 @@ module type S = sig
 
     val execute : t -> Field.value array -> Res.t result
     val reset : t -> unit result
+    val sqlstate : t -> string
     val close : t -> unit result
   end
 
@@ -162,6 +163,7 @@ module type S = sig
   val commit : t -> unit result
   val rollback : t -> unit result
   val prepare : t -> string -> Stmt.t result
+  val sqlstate : t -> string
 end
 
 module B = Binding_wrappers

lib/mariadb.mli

@@ -154,6 +154,12 @@ module type S = sig
           were after [stmt] was prepared, and frees up any {!Res.t} produced by
           [stmt]. *)
 
+    val sqlstate : t -> string
+      (** [sqlstate stmt] is the SQLSTATE with MariaDB extensions indicating the
+          status of the previous execution of the statement. The string
+          ["00000"] is returned if no error occurred or if the statement has not
+          been executed. *)
+
     val close : t -> unit result
 			(** [close stmt] closes the prepapred statement [stmt] and frees
 					any allocated memory associated with it and its result. *)
@@ -275,6 +281,10 @@ module type S = sig
 		(** [prepare mariadb query] creates a prepared statement for [query].
 				The query may contain [?] as placeholders for parameters that
 				can be bound by calling [Stmt.execute]. *)
+
+  val sqlstate : t -> string
+    (* [sqlstate mariadb] is the SQLSTATE with MariaDB extensions of the last
+     * operation on [mariadb]. Returns ["00000"] if no error occurred. *)
 end
 
 (** The module for blocking MariaDB API calls. It should be possible to call

lib/nonblocking.ml

@@ -211,6 +211,8 @@ let prepare mariadb query =
       `Ok (prepare_start mariadb stmt query, prepare_cont mariadb stmt)
   | None -> `Error (Common.error mariadb)
 
+let sqlstate = Common.sqlstate
+
 module Res = struct
   type t = [`Nonblocking] Common.Res.t
 
@@ -344,6 +346,8 @@ module Stmt = struct
 
   let next_result_cont stmt status =
     handle_next stmt (B.mysql_stmt_next_result_cont stmt.Common.Stmt.raw status)
+
+  let sqlstate = Common.Stmt.sqlstate
 end
 
 module type Wait = sig