Re: [Cppcms-users] Is dbixx::row available in an associative arary?

[Artyom <art...@ya...>]

> 
> Hello,
> 
> 
> http://art-blog.no-ip.info/wikipp/en/page/ref_dbixx_row
> It's  not too clear from the documentation above if the data in dbixx::row is 
> available from an associative array.
> 
> dbixx::result  res;
> sql<<"SELECT name,age,birthday "  
>      "FROM  person ", res;
> 
> dbixx::row myRow;
> while (res.next(myRow))  {
>     // Can we do something like the  following?
>     std::string name =  myRow["name"];
>     // ...
> }

No you can't. The reason is simple - what type should operator[] should return?
Today operator[] overloaded to check if the variable is null.

> 
> My problem is that I  want to pass the row data into my classes' constructors.
> 
> Currently, I  must declare temporary variables on the stack, extract the row 
> data into  those variables, and pass them to my object constructors:
> 
> 
> dbixx::row  myRow;
> while (res.next(myRow)) {
>     std::string  tmp_name;
>     int tmp_age, tmp_birthday;
>      myRow >> tmp_name >> tmp_age >>  tmp_birthday;
>     // Call my class  constructor:
>     myClass person = myClass(tmp_name, tmp_age,  tmp_birthday);
> }
> 
> I'd be neater if we could do something like  this:
> 
> 
> 
> dbixx::row myRow;
> while (res.next(myRow))  {
>     // Call my class constructor:
>      myClass person = myClass(myRow["name"], myRow["age"],  
myRow["birthday"]);
> }
> 
> I know there is the method fetch():
> bool  fetch(int idx,int &value);  
> but again, it requires temporary variables  to be created, adding to code bloat 
>
> and overheads... :-/
> 
> 
> Or how  do you handle such things?
> 
> Thanks,
> 
> Augustin.
> 


I've added an option to fetch a value by column index (not name)
as r.get<std::string>(1), take a look on the version in trunk.

However...

I'd suggest to take a look on cppdb - this is a new project
drop in replacement of dbixx, unlike dbixx it does not depend on
libdbi library but rather implements all by its own. Its API
is different from dbixx but conversion is mostly mechanical.

There you can do:

cppdb::result r = sql << "SELECT name,age,birthday FROM users";
while(r.next()) {
     myClass person = myClass(r.get<std::string>("name"), r.get<int>("age"),  
r.get<std::tm>("birthday"));
}


You may check the beta version at:

   https://cppcms.svn.sourceforge.net/svnroot/cppcms/cppdb/trunk

The documentation is avalible via Doxygen. So after checkout
run doxygen and take a look on the file html/index.html for docs. i.e.:

  svn co https://cppcms.svn.sourceforge.net/svnroot/cppcms/cppdb/trunk cppdb
  cd cppdb
  doxygen
  cd html
  firefox index.html


It will be officially released withing a week (only some last toches on 
documentation
should be done)

Regards,
  Artyom