Entwicklung Archives - Page 7 of 14

Spring Data JPA Postgres UUID @Id

By Darko Luketic 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I read lots of outdated info on this matter.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;
}
}

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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
);

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create table page

(

id uuid default gen_random_uuid() not null

constraint "primary"

primary key

);

And you…

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Easily remember ManyToMany ManyToOne OneToMany

By Darko Luketic 14. March 2022 1 min read 0 Comments

ManyToMany in a Person Blog Relationship A Person can be a subscriber of many blogs. A Blog can have many subscribers.

const Person = {
isSubscriberOfBlogs: []
}
const Blog = {
subscribers = []
}

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const Person = {

isSubscriberOfBlogs: []

}

const Blog = {

subscribers = []

}

But since this is an inefficient way to manage usually a proxy table is used with [PersonID], [BlogID], aka the 2 related data models. ManyToOne and OneToMany in a Person Blog Relationship A…

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Vue composition api: ensure variable is not null

By Darko Luketic 11. March 2022 1 min read 0 Comments

I ran into a problem where I was loading data from the backend in App.vue and when loaded that data would be inserted into a vuex store and in another component queried. However the loading took longer than expected and a data race happened. The route destination rendered faster than the backend could deliver data…

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Why do I need microservices?

By Darko Luketic 21. February 2022 3 min read 0 Comments

Microservices are supposed to solve the scaling problem. Aka the solution to a monolith only being able to handle so many requests / second is microservices that potentially have replicas.

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Upgrade Keycloak Standalone with Postgres from 16.1.0 to 17.0.0 with custom port behind nginx reverse proxy

By Darko Luketic 17. February 2022 1 min read 0 Comments

What a nightmare. You’re using keycloak and are upgrading from Wildfly 16.1.0 to Quarkus 17.0.0. You’re also listening on a non-standard port, that isn’t 8080, but 23232. You’re using a reverse proxy like nginx for TLS and Keycloak is connected via plain http with nginx. Grab your standalone.xml found in /standalone/configuration/standalone.xml and find your postgres…

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