[Angel Fernández]

Perdón, al hacer vista previa de mensaje, el código delphi se veía bien, pero al enviar la respuesta definitiva me lo formatea mal.

Vuelvo a enviar el código delphi formateado:

Código Delphi [-]
procedure TMDOSQL.Prepare;
var
  stmt_len: Integer;
  res_buffer: array[0..7] of Char;
  type_item: Char;
begin
  if FCursor = '' then
    FCursor := Name + RandomString(8);
  CheckClosed;
  FBase.CheckDatabase;
  FBase.CheckTransaction;
  if FPrepared then
    exit;
  if (FSQL.Text = '') then
    MDOError(mdoeEmptyQuery, [nil]);
  if not ParamCheck then
    FProcessedSQL.Text := FSQL.Text
  else
    PreprocessSQL;
  if (FProcessedSQL.Text = '') then
    MDOError(mdoeEmptyQuery, [nil]);
  try
    Call(isc_dsql_alloc_statement2(StatusVector, DBHandle,
                                    @FHandle), True);
    Call(isc_dsql_prepare(StatusVector, TRHandle, @FHandle, 0,
               PChar(FProcessedSQL.Text), Database.SQLDialect, nil), True);
    { After preparing the statement, query the stmt type and possibly
      create a FSQLRecord "holder" }
    { Get the type of the statement }
    type_item := Char(isc_info_sql_stmt_type);
    Call(isc_dsql_sql_info(StatusVector, @FHandle, 1, @type_item,
                         SizeOf(res_buffer), res_buffer), True);
    if (res_buffer[0] <> Char(isc_info_sql_stmt_type)) then
      MDOError(mdoeUnknownError, [nil]);
    stmt_len := isc_vax_integer(@res_buffer[1], 2);
    FSQLType := TMDOSQLTypes(isc_vax_integer(@res_buffer[3], stmt_len));
    { Done getting the type }
    case FSQLType of
      SQLGetSegment,
      SQLPutSegment,
      SQLStartTransaction: begin
        FreeHandle;
        MDOError(mdoeNotPermitted, [nil]);
      end;
      SQLCommit,
      SQLRollback,
      SQLDDL, SQLSetGenerator,
      SQLInsert, SQLUpdate, SQLDelete, SQLSelect, SQLSelectForUpdate,
      SQLExecProcedure: begin
        { We already know how many inputs there are, so... }
        if (FSQLParams.FXSQLDA <> nil) and
           (Call(isc_dsql_describe_bind(StatusVector, @FHandle, Database.SQLDialect,
                                        FSQLParams.FXSQLDA), False) > 0) then
          MDODatabaseError;
        FSQLParams.Initialize;
        if FSQLType in [SQLSelect, SQLSelectForUpdate,
                        SQLExecProcedure] then
        begin
          { Allocate an initial output descriptor (with one column) }
          FSQLRecord.Count := 1;
          { Using isc_dsql_describe, get the right size for the columns... }
          Call(isc_dsql_describe(StatusVector, @FHandle, Database.SQLDialect, FSQLRecord.FXSQLDA), True);
          if FSQLRecord.FXSQLDA^.sqld > FSQLRecord.FXSQLDA^.sqln then
          begin
            FSQLRecord.Count := FSQLRecord.FXSQLDA^.sqld;
            Call(isc_dsql_describe(StatusVector, @FHandle, Database.SQLDialect, FSQLRecord.FXSQLDA), True);
          end else if FSQLRecord.FXSQLDA^.sqld = 0 then
            FSQLRecord.Count := 0;
          FSQLRecord.Initialize;
        end;
      end;
    end;
    FPrepared := True;
    if not (csDesigning in ComponentState) then
      MonitorHook.SQLPrepare(Self);
  except
    on E: Exception do
    begin
      if (FHandle <> nil) then
        FreeHandle;
      raise;
    end;
  end;
end;

Disculpad.