google app engine - How to query JDO persistent objects in unowned relationship model? -

I am trying to migrate my app from PHP and RDBMS (MySQL) to Google App Engine and I find it difficult Time is the relationship between the data model and the JDO. In my current app I use a lot of join queries:

  Select users Name, comments.com, from users, comments are where users.user_id = comments.user_id and users.email = 'john as I have understood, this is not supported in this way, so the queries are not supported, so the only way to store data? ) Is using unique relationships and "foreign" keys. There is a document about this, but there is no useful example. So far I have something like this:  
  @property, enable public class users {@PrimaryKey @Persistent (valueStrategy = IdGeneratorStrategy.INDNTITY) private key; @Print Name of Private String; @Assistant Private String Email; @ Presentation Private Set & lt; Key & gt; CommentKeys; // Accessors ...} @ PRESERSpacePackaging Public Class Comments {@PrimaryKey @ Persistent (Value Strategy = ID Generator.Tradent.Indi) Private Key; @printerest private string comment; @Priyant Private Date Comment Date; @ Dear private key user; // Entryer ...}  
 
 So, how do I get a list with a comment, name, comment and date in a comment? I see that I may run away with 3 questions, but it seems wrong and will make unnecessary overhead. Please help me with some code examples. 
 
 - Paul. 
 

Only you can comment on that ZodoAql which

select this. Name, commentVar.comment from mydomain.Users WHERE this .key == commentVar.userKey & amp; Amp; This is .email = 'john@example.com' versions of the maindomain. Comment Comment Description

What GAE / J is to implement is to answer Google.