go_pg_json.go

package main

import (
	"fmt"

	"gorm.io/datatypes"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
)

type Planet struct {
	ID            uint   `gorm:"primaryKey;autoIncrement"`
	Name          string `gorm:"unique;type:string;size:100"`
	NumSatellites uint32
	Specs         JSONMap // from https://gist.github.com/jquiterio/ef31f8640ebe2960a8fd3a0bcccd9689

var db *gorm.DB

func init() {
	var err error
	dsn := "host=localhost user=medium dbname=medium port=5432 sslmode=disable"
	if db, err = gorm.Open(postgres.Open(dsn), &gorm.Config{}); err != nil {
		panic(err)
	}
	// automigrate table planets
	db.AutoMigrate(&Planet{})
}

func CreatePlanet() {
	// declaring planet specs
	earthSpecs := map[string]interface{}{
		"alt_name":         "gaia",
		"main_composition": []string{"nitrogen", "oxygen"},
		"others": map[string]interface{}{
			"is_nice":             true,
			"orbital_period_days": 365,
		},
	}
	marsSpecs := map[string]interface{}{
		"main_composition": []string{
			"carbon dioxide",
			"argon",
			"nitrogen",
			"oxygen",
		},
		"is_red": true,
		"others": map[string]interface{}{
			"is_nice":             "hum...",
			"orbital_period_days": 686,
		},
	}
	jupiterSpecs := map[string]interface{}{
		"main_composition": []string{"hydrogen", "helium"},
	}
	// creating Array of Planets
	earth := Planet{Name: "Earth", NumSatellites: 1, Specs: JSONMap(earthSpecs)}
	mars := Planet{Name: "Mars", NumSatellites: 2, Specs: JSONMap(marsSpecs)}
	jupiter := Planet{Name: "Jupiter", NumSatellites: 79, Specs: JSONMap(jupiterSpecs)}
	planets := []Planet{earth, mars, jupiter}

	db.Debug().Create(&planets)
}

func GetPlanetsWithAltName() {
	planets := []Planet{}
	db.Debug().Find(&planets, datatypes.JSONQuery("specs").HasKey("alt_name"))
	fmt.Printf("%+v", planets)
}

func GetPlanetByAltName(alt_name string) {
	planets := []Planet{}
	db.First(&planets, datatypes.JSONQuery("specs").Equals(alt_name, "alt_name"))
	fmt.Printf("%+v", planets)
}

func GetPlanetsByComposition(composition string) {
	planets := []Planet{}
	db.Debug().Model(&Planet{}).Find(&planets, datatypes.JSONQuery("specs").HasKey("main_composition", composition))
	fmt.Printf("%+v", planets)
}

func GetAllPlanets() {
	planets := []Planet{}
	db.Find(&planets)
	fmt.Printf("%+v", planets)
}

func UpdatePlanetByItsComposition(composition string) {
	planets := []Planet{}
	updatedPlanets := []Planet{}
	db.Debug().Model(&Planet{}).Find(&planets, datatypes.JSONQuery("specs").HasKey("main_composition", composition))
	for _, planet := range planets {
		specs := planet.Specs
		specs["type"] = "cool!"
		planet.Specs = JSONMap(specs)
		db.Save(&planet)
	}
	db.Debug().Model(&Planet{}).Find(&updatedPlanets, datatypes.JSONQuery("specs").HasKey("type", "cool!"))
	fmt.Printf("%+v", updatedPlanets)
}

func DeletePlanetWithoutAComposition(composition string) {
	planets := []Planet{}
	db.Not(datatypes.JSONQuery("specs").HasKey("main_composition", composition)).Find(&planets)
	for _, planet := range planets {
		db.Delete(&planet)
	}
	//double check
	db.Find(&planets)
	fmt.Printf("%+v", planets)
}

func main() {
	CreatePlanet()
	GetAllPlanets()
	GetPlanetsWithAltName()
	GetPlanetByAltName("gaia")
	GetPlanetsByComposition("oxygen")
	UpdatePlanetByItsComposition("oxygen")
	DeletePlanetWithoutAComposition("oxygen")
}