java - How to configure a polymorphic Map relationship with EBean? -


i have seen examples of setting map association ebean. examples i've seen typically support schema below.

with such schema, jpa mapping of video have property public list<videometadata> metadata;.

how can change metadata map instead of list, instance public map<string, string> metadata;?

create table video (   id uuid primary key,   title varchar(255) not null );  create table metadata (   id bigserial primary key,   video_id uuid not null, -- relationship not polymorphic   key varchar(255) not null,   value varchar(255) not null );

i have defined polymorphic relationship between metadata , video (and photo, , on...). video can have multiple metadata, can photo.

the polymorphic relationship configured inheritancetype.single_table , "describable" identified via combination of describable_type , describable_id.

the database schema looks this.

create table video (   id uuid primary key,   title varchar(255) not null );  create table metadata (   id bigserial primary key,   describable_id uuid not null, -- have polymorphism   describable_type varchar(255) not null, -- have polymorphism   key varchar(255) not null,   value varchar(255) not null );

and models (in case it's relevant, i'm using ebean)...

package models;  import io.ebean.model; import javax.persistence.id; import java.util.uuid; import play.data.validation.constraints; import javax.persistence.*; import java.util.list;  @entity public class video extends model {      @id     public uuid id;      @constraints.required     public string title;      @elementcollection(fetch = fetchtype.eager)     @onetomany(mappedby = "describable", cascade = cascadetype.all)     public list<videometadata> metadata;  } 
package models;  import io.ebean.model; import play.data.validation.constraints;  import javax.persistence.*;  @entity @inheritance(strategy = inheritancetype.single_table) @discriminatorcolumn(     name = "describable_type",     discriminatortype = discriminatortype.string ) public abstract class metadata extends model {      @id     @generatedvalue     public long id;      @constraints.required     public string key;      @constraints.required     public string value;  } 
package models;  import javax.persistence.discriminatorvalue; import javax.persistence.entity; import javax.persistence.manytoone;  @entity @discriminatorvalue("video") public class videometadata extends metadata {      @manytoone(optional = false)     public video describable;  } 
package models;  import javax.persistence.discriminatorvalue; import javax.persistence.entity; import javax.persistence.manytoone;  @entity @discriminatorvalue("photo") public class imagemetadata extends metadata {      @manytoone(optional = false)     public photo describable;  }


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