2013/10/17 Wim Dumon <w...@emweb.be>
> Hi,
>
> The issue here is indeed that A.h has to include B.h and B.h has to
> include A.h, which will not work, by C++'s preprocessor design. There's two
> possible ways around this:
>
> 1. don't use the typedefs, and only forward declare 'class Country;' in
> City.h and 'class City;' in Country.h
>
> 2. put the forward declaration and typedefs in a separate file (MyFwd.h),
> and include that file in ever Dbo file.
>
> BR,
> Wim.
>
>
>
> 2013/10/17 Muhammad Nasser Al-Noimi <mnno...@gmail.com>
>
>> Hi,
>>
>> Ihave aC++ trouble and I'm wondering if someone can help me here. Iwant
>> to deal with database using Wt::Dbo. I want to put each table definition
>> into a separate source file. I have OneToMany relation between two
>> tables, When I put each class into separate files I got the error:
>> "'Cities' does not name a type". I got no error If classes are in the
>> same source file.
>> I wrote two classes "Country" and "City" with some helper typedefs as
>> following:
>>
>> //Country.h ----------------------------------------------
>> #ifndef COUNTRY_H
>> #define COUNTRY_H
>>
>> #include <Wt/Dbo/Dbo>
>> #include <string>
>>
>> #include "database.h"
>>
>> namespace dbo = Wt::Dbo;
>>
>> // Country
>> class Country;
>> typedef dbo::ptr<Country> CountryPtr;
>> typedef dbo::collection< dbo::ptr<Country> > Countries;
>>
>> class Country {
>> public:
>> Cities cities;
>>
>> template<class Action>
>> void persist(Action& a)
>> {
>> dbo::hasMany(a, cities, dbo::ManyToOne, "country");
>> }
>> };
>>
>> #endif // COUNTRY_H
>>
>> // city.h -----------------------------------------------------
>> #ifndef CITY_H
>> #define CITY_H
>>
>> #include <Wt/Dbo/Dbo>
>> #include <string>
>>
>> #include "database.h"
>>
>> namespace dbo = Wt::Dbo;
>>
>> // City
>> class City;
>> typedef dbo::ptr<City> CityPtr;
>> typedef dbo::collection< dbo::ptr<City> > Cities;
>>
>> class City {
>> public:
>> CountryPtr country;
>>
>> template<class Action>
>> void persist(Action& a)
>> {
>> dbo::belongsTo(a, country, "country");
>> }
>> };
>>
>> #endif // CITY_H
>>
>> Thanks a lot
>>
>>
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>
>
>
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