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Spring Data JPA fixtures

14. March 2022 | 1 min read | 0 Comments |

What are fixtures? Fixed data that is always present in the database. You can think of it as the initial dataset. application.properties

spring.jpa.hibernate.ddl-auto=create
spring.jpa.generate-ddl=true
spring.jpa.open-in-view=false
spring.sql.init.mode=always
spring.sql.init.data-locations=classpath:db/data.sql
spring.jpa.defer-datasource-initialization=true

spring.jpa.hibernate.ddl-auto=create

spring.jpa.generate-ddl=true

spring.jpa.open-in-view=false

spring.sql.init.mode=always

spring.sql.init.data-locations=classpath:db/data.sql

spring.jpa.defer-datasource-initialization=true

The documentation speaks of “the root classpath”, not knowing Java well I had no idea what that means and an answer on Stackoverflow was of course wrong. It’s not the “src” dir,…

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Spring Data JPA Postgres UUID @Id

14. March 2022 | 1 min read | 2 Comments |

I read lots of outdated info on this matter. Using PostgreSQL v13+ there is a function called gen_random_uuid(). See the manual page of Postgres UUID. Here’s an example entity called Page

package de.icod.blog.model;
import javax.persistence.*;
import java.util.UUID;
@Entity
@Table(name = "page")
public class Page {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id", nullable = false, columnDefinition = "UUID default gen_random_uuid()")
private UUID id;
public UUID getId() {
return id;
}
public void setId(UUID id) {
this.id = id;
}
}

package de.icod.blog.model;

import javax.persistence.*;

import java.util.UUID;

@Entity

@Table(name = "page")

public class Page {

@Id

@GeneratedValue(strategy = GenerationType.AUTO)

@Column(name = "id", nullable = false, columnDefinition = "UUID default gen_random_uuid()")

private UUID id;

public UUID getId() {

return id;

}

public void setId(UUID id) {

this.id = id;

}

As you see you can append the columnDefinition to the @Column annotation. “UUID default gen_random_uuid()” This translates to following SQL

create table page
(
id uuid default gen_random_uuid() not null
constraint "primary"
primary key
);

create table page

(

id uuid default gen_random_uuid() not null

constraint "primary"

primary key

);

And you…

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