Google Datastore Entity does not return ID. Entity ID is null

Question

I have a product entity which is extended from DataType Entity. Like this:

@

Entity(name = "Product")
@Getter
@Setter
public class ProductEntity extends DataTypeEntity{

        public Date created;
        String name;
        String url;
        String code;
        String description;
        String fixedCost;
}

@Getter
@Setter
@NoArgsConstructor
public class DataTypeEntity {

    @Id
    public Long id;
    public Date created;
    public Date lastUpdated;

}

And I have ProductDao to retrieve products from the database

@Repository
public interface ProductDao extends DatastoreRepository<ProductEntity, Long> {

    List<ProductEntity> findAll();

    List<ProductEntity> findByCode(String code);

And when I make the query. The ID is null.

Click here to see the screenshot of the query

My Google Cloud datastore entity is like this: Click here to see the screenshot of datastore entity

I would like to retrieve Key Product id:5748154649542656 from this entity. Please help. Thanks in advances

score 0 · Answer 1 · answered May 13 '20 at 20:47

Using @Inheritance

Entity(name = "Product")
@Getter
@Setter
public class ProductEntity extends DataTypeEntity{

        public Date created;
        String name;
        String url;
        String code;
        String description;
        String fixedCost;
}

new DataTypeEntity will be like this

@Getter
@Setter
@NoArgsConstructor
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
public class DataTypeEntity {

    @Id
    public Long id;
    public Date created;
    public Date lastUpdated;

}

or using @MappedSuperclass

@Getter
@Setter
@NoArgsConstructor
@MappedSuperclass  
public class DataTypeEntity {

    @Id
    public Long id;
    public Date created;
    public Date lastUpdated;

}

Thanks for the answer. But Spring framework doesnt have those annotation as I am using google data cloud. I believe what you are mentioning is Hibernate inheritance annotation — Win Han, May 15 '20 at 10:48

score 0 · Answer 2 · answered May 18 '20 at 08:38

I set up a Spring Boot App with Datastore following this quickstart and I modified the Book class to inherit from your DataTypeEntity.

Book.java:

package com.example.demo;

import com.DataTypeEntity;
import org.springframework.cloud.gcp.data.datastore.core.mapping.Entity;

@Entity(name = "books")
public class Book extends DataTypeEntity{
    String title;

    String author;

    int year;

    public Book(String title, String author, int year) {
            this.title = title;
            this.author = author;
            this.year = year;
    }

    public long getId() {
            return this.id;
    }

    @Override
    public String toString() {
            return "Book{" +
                            "id=" + this.id +
                            ", created='" + this.created + '\'' +
                            ", lastUpdated='" + this.lastUpdated + '\'' +
                            ", title='" + this.title + '\'' +
                            ", author='" + this.author + '\'' +
                            ", year=" + this.year +
                            '}';
    }
}

DataTypeEntity.java:

package com;

import com.google.cloud.Date;
import org.springframework.data.annotation.Id;

public class DataTypeEntity {

    @Id
    public Long id;
    public Date created;
    public Date lastUpdated;

}

When getting the books, the ID property was filled as expected

Are you able to see the ID field in the properties section of your entity in the console? For example: https://i.stack.imgur.com/4nEqw.png — Jose V, May 19 '20 at 15:54
Hi @Jose V I do not have the id field in the properties. I want the Id from the Key Literal or Key. Is there a way to do that? — Win Han, May 21 '20 at 09:05

Google Datastore Entity does not return ID. Entity ID is null

2 Answers2