If I understand,
when we call only ->select('p'), and then $post->getUser(); we have 2
queries to the database.
But, if we put ->select('p, u')->from(..., 'p')->join(..,'u'), then we have
only one query to database (we will return all data via one query), when we
call $post->getUser();
So, if we plan to use users, then we will put ->select('p, u')->join('u').., ,
because this is better way. Correct?
недеља, 04. мај 2014. 17.35.30 UTC+2, Marco Pivetta је написао/ла:
>
> Hi Spezia,
>
> You may want to look at this specific paragraph in the docs:
> http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html#joins
>
> In general, the idea is that in DQL you will only ever get back the
> so-called "root" of your selection, which in your example is the "p" (Post)
> entity.
> If you then also select "u, c", (fetch-join) those will be "hydrated" into
> "p", and become part of a Post's associations.
>
> It is important to note that you should not filter associations and
> fetch-join them, as that will hydrate wrong data into your Post entity.
>
>
> Marco Pivetta
>
> http://twitter.com/Ocramius
>
> http://ocramius.github.com/
>
>
> On 4 May 2014 17:31, spezia <[email protected] <javascript:>> wrote:
>
>> I am confused about Doctrine. I have the experience with sql.
>> I am not sure when to use join, left join methods,..
>>
>> Example: we have the 3 tables: user, post and comments, and the classic
>> connections among them...
>>
>> 1) Example
>>
>> $post = ...->select('p')
>> ->from('Post p')
>> ->getQuery()
>> ->getResult();
>>
>> If I want an user, I can get it: $post->getUser(); or comments:
>> $post->getComments();
>> I do not need next:
>>
>> $post = ...->select('p')
>> ->from('Post p')
>> ->join('p.user', 'u')
>> ->join('p.comments', 'c')
>> ->getQuery()
>> ->getResult();
>>
>> I get the same result.
>> Also I am not sure when I need something like this
>> ->select('p, u, c')...
>>
>> Can someone help me :)
>> Thanks
>>
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>
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