Sorry about the first example I just wrote it off the top of my head. Here
is an actual example I attempted.
This is a method inside of a class that extends the auto generated
MerchantDao. The mapper() is for a Merchant Pojo also auto generated.
public class MerchantDaoExt extends MerchantDao {
...
public List<Merchant> fetchMerchantsByGroupId(Long groupId) {
return using(configuration())
.select()
.from(Tables.MERCHANT)
.join(Tables.MERCHANT_GROUP_MAPPING)
.onKey()
.where(Tables.MERCHANT_GROUP_MAPPING.GROUP_ID.eq(groupId))
.fetch()
.map(mapper());
}
The compilation error I get is.
The method map(RecordMapper<? super Record,E>) in the type Result<Record>
is not applicable for the arguments (RecordMapper<MerchantRecord,Merchant>)
To me it seems like when you use selectFrom(? extends Table) its able to
hint to the sql builder the type of the Record. When you do just a
select() it only knows it will be a Record but not what type. Am I missing
an alternate way to do this?
Thanks
On Thursday, January 22, 2015 at 12:33:45 PM UTC-5, Lukas Eder wrote:
>
> Hello,
>
> 2015-01-22 5:01 GMT+01:00 Bill O'Neil <[email protected] <javascript:>>:
>
>> 1. Is it possible to reuse auto generated RecordMappers from the dao
>> objects? I have been trying to find a way to do something like.
>>
>> List<User> users = using(configuration())
>> .selectFrom(Tables.USER)
>> .from(Tables.USER)
>> .join(Tables.ROLES)
>> .onKey()
>> .where(Tables.ROLES.ROLE.eq("admin"))
>> .fetch()
>> .map(mapper());
>>
>> This doesn't quite work is there a way to do it? Essentially a simple
>> join and only return a pojo from one of the tables.
>>
>
> The DAO.mapper() method is public. Why doesn't calling it work for you?
> Do note, it doesn't do anything magic, out-of-the-box. It simply calls
> through to the DefaultRecordMapper, caching the instance in the DAO
> instance.
>
> The one thing that is obviously not correct is your repeating the "FROM
> USER" clause twice. You should write
>
> using(configuration())
> .select()
> .from(Tables.USER)
> .join(Tables.ROLES)
> .onKey()
>
> 2. Is there a way to return multiple mapped pojos from a query. Possibly
>> Combining JOOQ and JOOL or something.
>>
>> List<Tuple2<User, Role>> users = using(configuration())
>> .selectFrom(Tables.USER)
>> .from(Tables.USER)
>> .join(Tables.ROLES)
>> .onKey()
>> .fetch()
>> .map(user.mapper(), role.mapper());
>>
>> I have been using slick in scala which allows you to tuple a bunch of
>> case classes into a single result. I was curious if you can do something
>> similar in JOOQ easily.
>>
>
> That sounds very interesting indeed! We haven't thought about this yet.
> Do note, though, that this only works if your USER and ROLES tables do not
> share the same column names, though. In case they don't, you can do
> something like that:
>
> List<Tuple2<User, Role>> users = using(configuration())
> .select()
> .from(Tables.USER)
> .join(Tables.ROLES)
> .onKey()
> .fetch()
> .map(r -> tuple(user.mapper().map(r), role.mapper().map(r)));
>
> We'll keep this use-case in mind when implementing jOOQ 3.6, where we'll
> tackle support for nested records both on a SQL and on a mapping level.
>
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