Create a function to get the contents of the database in Go

I'm going to write about a function that takes all the desired content from the database. I already have something in the database

Make an interface {} variable an argument of a function with a fixed type Simple operation of "Mysql" with "Golang" x "Gorm" [Go + gin + gorm] Try adding a login function to the web application From Mysql connection in Go to data allocation to structure Oreore configuration API made with Gin and GORM

install

import (
    _ "github.com/go-sql-driver/mysql"//This needs to be added by myself
	"github.com/jinzhu/gorm"
)
//When not
//go get github.com/jinzhu/gorm
//go get github.com/go-sql-driver/mysql

First, connect to the database

main.go

func openGormDB() *gorm.DB { // localhost
	DBMS := "mysql"
	USER := "user"//mysql username
	PASS := "password"//password
	PROTOCOL := "tcp(localhost:3306)"
	DBNAME := "sample"//Database name

	CONNECT := USER + ":" + PASS + "@" + PROTOCOL + "/" + DBNAME + "?charset=utf8&parseTime=True&loc=Local"
	db, err := gorm.Open(DBMS, CONNECT)
	if err != nil {
		panic(err)
	}
	return db
}

This is the contents of the database

main.go

type ShiromiyaChannelInfos struct {
	//ID              uint64
	ChannelID       string
	ChannelName     string
	ViewCount       uint `gorm:"type:int"`
	SubscriberCount uint `gorm:"type:int"`
	VideoCount      uint `gorm:"type:int"`
	CreatedAt       time.Time
}

Function that takes the contents of the database Write for each table

Function that takes the contents of the database

//I have to write a function like this one many times
func GetDBShiro() []ShiromiyaChannelInfos/*<=①*/ {
	db := openGormDB()
	var shiroInfo []ShiromiyaChannelInfos/*<=①*/
	db.Find(&shiroInfo)/*<=①*/
	db.Close()
	return shiroInfo/*<=①*/

func GetDBHashi() []HashibaChannelInfos/*<=①*/ {
	db := openGormDB()
	var hashiInfo []HashibaChannelInfos/*<=①*/
	db.Find(&hashiInfo)/*<=①*/
	defer db.Close()
	return hashiInfo/*<=①*/
}

A function that connects to a database and gets all the contents of the target table Only the place where it was different from ① above The rest is almost the same

I have to write something like the above (function that takes the contents of the database) many times, so I summarized it

main.go

//This is the finished product
func AllGetDBChannelInfo(chInfo string) (interface{}, error) {
	db := openGormDB()
	defer db.Close()

	switch chInfo {
	case "ShiromiyaChannelInfos":
		var channelInfo []entity.ShiromiyaChannelInfos
		db.Find(&channelInfo)
		return channelInfo, nil
	case "HashibaChannelInfos":
		var channelInfo []entity.HashibaChannelInfos
		db.Find(&channelInfo)
		return channelInfo, nil
	case "ChannelInfos":
		var videoInfo []entity.VideoInfos
		db.Find(&videoInfo)
		return videoInfo, nil
	default:
		return nil, errors.New("That db_no name")
	}
}

problem: AllGetDB must overwrite AllGetDB later when adding a function

GetDB has many functions with many duplicates. But you don't have to overwrite the function, just add it