Bidirectional relationship in yaml
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bsr
Jul 27, 2010, 11:05:43 PM7/27/10
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Hello,
Anyone successful in defining a bidirectional relationship in yaml.
I am not sure the correct syntax for it. Please see the domain model,
and the yaml.
public class Person {
String fullname;
@OneToMany(mappedBy="person",cascade=CascadeType.ALL)
public List<Role> roles;
}
public class Role {
public RoleType roleType;
public String description;
public Person person;
}
public class RoleType {
public String roleName;
public String description;
}
YAML1:
RoleType(rt1):
roleName: ADMINISTRATOR
description: administrator
Role(prole1):
roleType: rt1
description: description
Person(person1):
fullname: test user
roles:
- role1
YAML2:
RoleType(rt1):
roleName: ADMINISTRATOR
description: administrator
Person(person1):
fullname: test user
roles:
- roleType: rt1
description: description
person: person1
YAML3:
RoleType(rt1):
roleName: ADMINISTRATOR
description: administrator
Person: &1
fullname: test user
roles:
- roleType: rt1
description: description
person: *1
None of it worked, giving transient error or "No previous reference
found for object of type ..." . Any pointer, highly appreciated.
thanks.
Anyone successful in defining a bidirectional relationship in yaml.
I am not sure the correct syntax for it. Please see the domain model,
and the yaml.
public class Person {
String fullname;
@OneToMany(mappedBy="person",cascade=CascadeType.ALL)
public List<Role> roles;
}
public class Role {
public RoleType roleType;
public String description;
public Person person;
}
public class RoleType {
public String roleName;
public String description;
}
YAML1:
RoleType(rt1):
roleName: ADMINISTRATOR
description: administrator
Role(prole1):
roleType: rt1
description: description
Person(person1):
fullname: test user
roles:
- role1
YAML2:
RoleType(rt1):
roleName: ADMINISTRATOR
description: administrator
Person(person1):
fullname: test user
roles:
- roleType: rt1
description: description
person: person1
YAML3:
RoleType(rt1):
roleName: ADMINISTRATOR
description: administrator
Person: &1
fullname: test user
roles:
- roleType: rt1
description: description
person: *1
None of it worked, giving transient error or "No previous reference
found for object of type ..." . Any pointer, highly appreciated.
thanks.
dirk
Jul 28, 2010, 10:49:47 AM7/28/10
to play-fr...@googlegroups.com
Try adding an annotation for the other side of the relationship as well:
public class Role {
public RoleType roleType;
public String description;
// You're missing this annotation:
@ManyToOne
public Person person;
}
public class Role {
public RoleType roleType;
public String description;
@ManyToOne
public Person person;
}
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bsr
Jul 28, 2010, 2:48:53 PM7/28/10
to play-framework
I am sorry.. I missed when I wrote the mail, it was already present..
Please let me know, in your experience whether u could define
bidirectional rel in yaml.. if you could show the syntax of yaml,
itwould help me.. thanks again..
> > play-framewor...@googlegroups.com<play-framework%2Bunsubscribe@go oglegroups.com>
> > .
Please let me know, in your experience whether u could define
bidirectional rel in yaml.. if you could show the syntax of yaml,
itwould help me.. thanks again..
> > .
Guillaume Bort
Jul 28, 2010, 2:52:00 PM7/28/10
to play-fr...@googlegroups.com
Role(prole1):
It should be
Role(role1):
right?
> To unsubscribe from this group, send email to play-framewor...@googlegroups.com.
> For more options, visit this group at http://groups.google.com/group/play-framework?hl=en.
>
>
--
Guillaume Bort, http://guillaume.bort.fr
For anything work-related, use g...@zenexity.fr; for everything else,
write guillau...@gmail.com
dirk
Jul 29, 2010, 10:15:45 AM7/29/10
to play-fr...@googlegroups.com
I think you also need an @Entity annotation on the model classes, eg:
@Entity
public class Role {
...
}
Play uses SnakeYAML. The documentation includes some examples:
http://code.google.com/p/snakeyaml/wiki/Documentation
Note that Play's syntax is slightly different. Instead of using &identifier, you put the identifier name in brackets after the model's class name and then you can just refer to it directly.
Here's an example that includes both one-to-many (City-Neighborhood) and many-to-many (User-Neighborhood) relationships:
City(capitalfederal):
name: Capital Federal
state: Buenos Aires
Neighborhood(villalugano):
name: Villa Lugano
city: capitalfederal
tags: "shopping, cafes"
Neighborhood(coghlan):
name: Coghlan
city: capitalfederal
tags: "cafes, bars"
User(john):
name: "John Smith"
email: jo...@john.com
lang: es
created: 2007-01-01
neighborhoods: [coghlan, villalugano]
User(frank):
name: "Frank Franken"
email: fr...@frank.com
lang: en
created: 2007-08-05
neighborhoods: [villalugano]
@Entity
public class Role {
...
}
Play uses SnakeYAML. The documentation includes some examples:
http://code.google.com/p/snakeyaml/wiki/Documentation
Note that Play's syntax is slightly different. Instead of using &identifier, you put the identifier name in brackets after the model's class name and then you can just refer to it directly.
Here's an example that includes both one-to-many (City-Neighborhood) and many-to-many (User-Neighborhood) relationships:
City(capitalfederal):
name: Capital Federal
state: Buenos Aires
Neighborhood(villalugano):
name: Villa Lugano
city: capitalfederal
tags: "shopping, cafes"
Neighborhood(coghlan):
name: Coghlan
city: capitalfederal
tags: "cafes, bars"
User(john):
name: "John Smith"
email: jo...@john.com
lang: es
created: 2007-01-01
neighborhoods: [coghlan, villalugano]
User(frank):
name: "Frank Franken"
email: fr...@frank.com
lang: en
created: 2007-08-05
neighborhoods: [villalugano]
bsr
Jul 29, 2010, 1:06:11 PM7/29/10
to play-framework
@Guillaume
It was (again) a typo .. With the example by Dirk, I could find the
right syntax.. I was wrong specifying role when creating person, but
should be other way around (at the owning entity).
@Dirk.
I can't thank enough, as I have been struggling with it. thanks for
the detailed example. For further reference, I keep the example below.
2 notes
1. Used @Table(name = "`user`") annotation as User is a reserved word
in PostgreSql
2. I had to reverse the many to many mapping as I considered
Neighborhood as the owning entity
~~~~~~~~~ Code ~~~~~~~~~~~~
Neighborhood.java
-----------------
package models;
import java.util.List;
import javax.persistence.*;
import play.db.jpa.Model;
@Entity
public class Neighborhood extends Model {
public String name;
@ManyToOne
public City city;//bi-directional one-to-many, owning side
public String tags;
@ManyToMany //owning side
public List<User> users;
}
User.java
------------
package models;
import java.util.*;
import javax.persistence.*;
import play.db.jpa.Model;
@Entity
@Table(name = "`user`")
public class User extends Model {
public String name;
public String email;
public String lang;
public Date created;
@ManyToMany(mappedBy="users") //inverse side of the relation
public List<Neighborhood> neighborhoods;
}
City.java
---------
package models;
import java.util.*;
import javax.persistence.*;
import play.db.jpa.Model;
@Entity
public class City extends Model {
public String name;
public String state;
@OneToMany(mappedBy = "city", cascade = CascadeType.ALL) //bi-
directional one-to-many, inverse side
public List<Neighborhood> neighborhoods;
}
YAML
----
#neighborhoods: [villalugano]
Neighborhood(villalugano):
name: Villa Lugano
city: capitalfederal
tags: "shopping, cafes"
users: [john, frank]
On Jul 29, 10:15 am, dirk <australiandevelo...@gmail.com> wrote:
> I think you also need an @Entity annotation on the model classes, eg:
> @Entity
> public class Role {
> ...
>
> }
>
> Play uses SnakeYAML. The documentation includes some examples:http://code.google.com/p/snakeyaml/wiki/Documentation
>
> Note that Play's syntax is slightly different. Instead of using &identifier,
> you put the identifier name in brackets after the model's class name and
> then you can just refer to it directly.
> Here's an example that includes both one-to-many (City-Neighborhood) and
> many-to-many (User-Neighborhood) relationships:
>
> City(capitalfederal):
> name: Capital Federal
> state: Buenos Aires
>
> Neighborhood(villalugano):
> name: Villa Lugano
> city: capitalfederal
> tags: "shopping, cafes"
>
> Neighborhood(coghlan):
> name: Coghlan
> city: capitalfederal
> tags: "cafes, bars"
>
> User(john):
> name: "John Smith"
> email: j...@john.com
> > Guillaume Bort,http://guillaume.bort.fr
> > write guillaume.b...@gmail.com
It was (again) a typo .. With the example by Dirk, I could find the
right syntax.. I was wrong specifying role when creating person, but
should be other way around (at the owning entity).
@Dirk.
I can't thank enough, as I have been struggling with it. thanks for
the detailed example. For further reference, I keep the example below.
2 notes
1. Used @Table(name = "`user`") annotation as User is a reserved word
in PostgreSql
2. I had to reverse the many to many mapping as I considered
Neighborhood as the owning entity
~~~~~~~~~ Code ~~~~~~~~~~~~
Neighborhood.java
-----------------
package models;
import java.util.List;
import javax.persistence.*;
import play.db.jpa.Model;
@Entity
public class Neighborhood extends Model {
public String name;
@ManyToOne
public City city;//bi-directional one-to-many, owning side
public String tags;
@ManyToMany //owning side
public List<User> users;
}
User.java
------------
package models;
import java.util.*;
import javax.persistence.*;
import play.db.jpa.Model;
@Entity
@Table(name = "`user`")
public class User extends Model {
public String name;
public String email;
public String lang;
public Date created;
@ManyToMany(mappedBy="users") //inverse side of the relation
public List<Neighborhood> neighborhoods;
}
City.java
---------
package models;
import java.util.*;
import javax.persistence.*;
import play.db.jpa.Model;
@Entity
public class City extends Model {
public String name;
public String state;
@OneToMany(mappedBy = "city", cascade = CascadeType.ALL) //bi-
directional one-to-many, inverse side
public List<Neighborhood> neighborhoods;
}
YAML
----
City(capitalfederal):
name: Capital Federal
state: Buenos Aires
#neighborhoods: [coghlan, villalugano]
name: Capital Federal
state: Buenos Aires
#neighborhoods: [villalugano]
Neighborhood(villalugano):
name: Villa Lugano
city: capitalfederal
tags: "shopping, cafes"
Neighborhood(coghlan):
name: Coghlan
city: capitalfederal
tags: "cafes, bars"
users: [john]
name: Coghlan
city: capitalfederal
tags: "cafes, bars"
On Jul 29, 10:15 am, dirk <australiandevelo...@gmail.com> wrote:
> I think you also need an @Entity annotation on the model classes, eg:
> @Entity
> public class Role {
> ...
>
> }
>
> Play uses SnakeYAML. The documentation includes some examples:http://code.google.com/p/snakeyaml/wiki/Documentation
>
> Note that Play's syntax is slightly different. Instead of using &identifier,
> you put the identifier name in brackets after the model's class name and
> then you can just refer to it directly.
> Here's an example that includes both one-to-many (City-Neighborhood) and
> many-to-many (User-Neighborhood) relationships:
>
> City(capitalfederal):
> name: Capital Federal
> state: Buenos Aires
>
> Neighborhood(villalugano):
> name: Villa Lugano
> city: capitalfederal
> tags: "shopping, cafes"
>
> Neighborhood(coghlan):
> name: Coghlan
> city: capitalfederal
> tags: "cafes, bars"
>
> User(john):
> name: "John Smith"
> lang: es
> created: 2007-01-01
> neighborhoods: [coghlan, villalugano]
>
> User(frank):
> name: "Frank Franken"
> email: fr...@frank.com
> lang: en
> created: 2007-08-05
> neighborhoods: [villalugano]
>
> created: 2007-01-01
> neighborhoods: [coghlan, villalugano]
>
> User(frank):
> name: "Frank Franken"
> email: fr...@frank.com
> lang: en
> created: 2007-08-05
> neighborhoods: [villalugano]
>
> > write guillaume.b...@gmail.com
dirk
Jul 29, 2010, 2:35:19 PM7/29/10
to play-fr...@googlegroups.com
I'm glad you got it working. Thanks for posting your sample code :)
I didn't realize you would need to include a "mappedBy" parameter for the @ManyToMany annotation. It seems like it should be able to figure that out automatically.
Guillaume, maybe this sample could be included in a Play/YAML documentation page?
I didn't realize you would need to include a "mappedBy" parameter for the @ManyToMany annotation. It seems like it should be able to figure that out automatically.
Guillaume, maybe this sample could be included in a Play/YAML documentation page?
To unsubscribe from this group, send email to play-framewor...@googlegroups.com.
Guillaume Bort
Jul 29, 2010, 2:45:20 PM7/29/10
to play-fr...@googlegroups.com
Yes sure can someone add it to the bug tracker with the attached sample?
bsr
Jul 29, 2010, 2:54:26 PM7/29/10
to play-framework
Dirk,
In the case of oneToMany, mappedBy is required to make the
relationship bi-directional. That is you can access the related entity
from both side. If you do not specify, the relation would be uni-
directional and a join table is automatically created. This is because
you prevent JPA from creating foreign key in the owning table.
In ManyToMany, mappedBy is not optional (http://download-
llnw.oracle.com/javaee/5/api/javax/persistence/ManyToMany.html). It is
required to specify the owning side, through which you persist the
relation.
thanks again.
Babu.
In the case of oneToMany, mappedBy is required to make the
relationship bi-directional. That is you can access the related entity
from both side. If you do not specify, the relation would be uni-
directional and a join table is automatically created. This is because
you prevent JPA from creating foreign key in the owning table.
In ManyToMany, mappedBy is not optional (http://download-
llnw.oracle.com/javaee/5/api/javax/persistence/ManyToMany.html). It is
required to specify the owning side, through which you persist the
relation.
thanks again.
Babu.
> > > > Guillaume Bort,http://guillaume.bort.fr
>
> > > > For anything work-related, use g...@zenexity.fr; for everything else,
> > > > write guillaume.b...@gmail.com
>
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> > > > For anything work-related, use g...@zenexity.fr; for everything else,
> > > > write guillaume.b...@gmail.com
>
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bsr
Jul 29, 2010, 3:08:30 PM7/29/10
to play-framework
Done... https://bugs.launchpad.net/play/+bug/611428
the program also attached.
On Jul 29, 2:45 pm, Guillaume Bort <guillaume.b...@gmail.com> wrote:
> Yes sure can someone add it to the bug tracker with the attached sample?
>
> Le 29 juil. 2010 à 20:35, dirk <australiandevelo...@gmail.com> a
the program also attached.
On Jul 29, 2:45 pm, Guillaume Bort <guillaume.b...@gmail.com> wrote:
> Yes sure can someone add it to the bug tracker with the attached sample?
>
> > %2Bunsubscribe@go oglegroups.com>
> > > > .
> > > > > For more options, visit this group at
> > > >http://groups.google.com/group/play-framework?hl=en.
>
> > > > --
> > > > Guillaume Bort,http://guillaume.bort.fr
>
> > > > For anything work-related, use g...@zenexity.fr; for everything
> > else,
> > > > write guillaume.b...@gmail.com
>
> > > > --
> > > > You received this message because you are subscribed to the
> > Google Groups
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> > .
> > > > .
> > > > > For more options, visit this group at
> > > >http://groups.google.com/group/play-framework?hl=en.
>
> > > > --
> > > > Guillaume Bort,http://guillaume.bort.fr
>
> > > > For anything work-related, use g...@zenexity.fr; for everything
> > else,
> > > > write guillaume.b...@gmail.com
>
> > > > --
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dirk
Aug 2, 2010, 7:50:37 PM8/2/10
to play-fr...@googlegroups.com
I've created a manual page. I included a link to my bzr branch in the bug report
https://bugs.launchpad.net/play/+bug/611428
http://bazaar.launchpad.net/~australiandeveloper/play/1.1-dev/revision/981
Please let me know if you have any suggestion and I'll modify it. I haven't worked with multiple yaml files before so perhaps there could be some information about that in there as well.
https://bugs.launchpad.net/play/+bug/611428
http://bazaar.launchpad.net/~australiandeveloper/play/1.1-dev/revision/981
Please let me know if you have any suggestion and I'll modify it. I haven't worked with multiple yaml files before so perhaps there could be some information about that in there as well.
dirk
Aug 2, 2010, 7:52:43 PM8/2/10
to play-fr...@googlegroups.com
I also posted a link to the fix for a problem that play has when parsing dates in a YAML file:
https://bugs.launchpad.net/play/+bug/611428
http://bazaar.launchpad.net/~australiandeveloper/play/1.1-dev/revision/979
https://bugs.launchpad.net/play/+bug/611428
http://bazaar.launchpad.net/~australiandeveloper/play/1.1-dev/revision/979
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