[odb-users] ODB Query using relation

[Adrian Imboden]

On 07.01.2014 09:33, Boris Kolpackov wrote:
> Hi Adrian,
>
> Adrian Imboden <mail at adrianimboden.ch> writes:
>
>> #pragma db object optimistic
>> class User
>> {
>> public:
>> 	#pragma db id auto
>> 	uint32_t id = 0;
>>
>> 	std::string name;
>>
>> 	#pragma db column("emailToken")
>> 	std::shared_ptr<Token> emailToken;
>>
>> 	odb::vector<std::shared_ptr<Token>> authTokens
>>
>> 	#pragma db version
>> 	size_t version = 0;
>> };
>>
>> #pragma db object optimistic
>> class Token
>> {
>> public:
>> 	#pragma db id auto
>> 	uint32_t id = 0;
>>
>> 	std::string hash;
>>
>> 	boost::posix_time::ptime expirationTime;
>>
>> 	#pragma db version
>> 	size_t version = 0;
>> };
>>
>> 1. Find all users that have an emailToken that has a given hash
> This one is easy since you can use pointed-to objects in queries
> (as discussed in the manual):
>
> typedef odb::query<User> query;
>
> db->query<User> (query::emailToken->hash == "1234");
Ah great. I must have overlooked this part.
>
>> 2. Find all users that have at least one authToken with a given hash
> This one is a bit trickier since ODB does not yet support querying
> of containers. So here you will need to use a view:
>
> #pragma db view object(User) object(Token = AuthToken: User::authTokens)
> struct UserView
> {
>    #pragma db column(User::id)
>    uint32_t id;
> };
>
> typedef odb::query<UserView> query;
>
> db->query<UserView> (query::AuthToken::hash == "1234");
>
> This will give you a list of User object ids that match the condition.
> Given that, you can then load the actual objects. Alternatively, you
> can pull the data members you are interested in directly in the view.
Great, I will use a view then. Is there already some idea how to 
implement this feature? If there is need, I could invest some time too.
>
>
>> PS: nice project by the way
> Thanks, I am glad you are enjoying it.
>
> Boris
>

Adi