Go edible daily use of GORM operation database | Go Theme month

preface

In daily development, it is inevitable to deal with the database, so how to operate the database in go ORM way? Let’s try it this time!

The connection

First we need to introduce GORM:

go get -u gorm.io/gorm
go get -u gorm.io/driver/mysql
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Then write the method to connect to the database:

import (
	"fmt"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

func ConnectDB(host, name, username, password string, port int) (db *gorm.DB, err error) {
	dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s? charset=utf8mb4", username, password, host, port, name)
	db, err = gorm.Open(mysql.Open(dsn), &gorm.Config{})
	return
}
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The migration

Gorm with transfer function, specific see: migration | gorm, here we need to define our data model (see model for specific rules can define | gorm) :

type Student struct {
	Id int `gorm:"primaryKey; autoIncrement"`
	Name string `gorm:"type:varchar(10); not null"`
	Age int `gorm:"type:int(3); not null"`
	Address string `gorm:"type:varchar(50); not null"`
}
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Then perform the migration:

func main(a) {
	db, err := ConnectDB("127.0.0.1"."juejin"."root"."root".3306)
	iferr ! =nil {
		panic(err)
	}
	err = db.AutoMigrate(&Student{})
	iferr ! =nil {
		panic(err)
	}
}
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Basic operation

Insert data

func InsertData(db *gorm.DB) {
	loop := 10
	students := make([]Student, 0, loop)
	for i := 1; i <= loop; i++ {
		students = append(students, Student{
			Name: fmt.Sprintf("Students % d", i),
			Age: i * 2,
			Address: fmt.Sprintf(No. % D, XXX City, XXX Province, i),
		})
	}
	err := db.Create(students).Error
	iferr ! =nil {
		panic(err)
	}
}
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Query data

func FindStudentById(db *gorm.DB, id int) (res Student) {
	err := db.Model(&Student{}).First(&res, id).Error
	iferr ! =nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		Error is also returned if no record is found in gorm, see https://gorm.io/zh_CN/docs/query.html
		panic(err)
	}
	return
}
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Update the data

func UpdateStudentNameById(db *gorm.DB, id int, newName string) (res bool) {
	rows := db.Model(&Student{}).Where(&Student{Id: id}).Updates(&Student{Name: newName}).RowsAffected
	if rows > 0 {
		res = true
	}
	return
}
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Delete the data

func RemoveStudentById(db *gorm.DB, id int) (res bool) {
	rows := db.Model(&Student{}).Delete(&Student{Id: id}).RowsAffected
	if rows > 0 {
		res = true
	}
	return
}
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Afterword.

This article is just a simple introduction to gorM usage, you can refer to the official Chinese documentation, which has more detailed examples: GORM Chinese documentation.

Finally, thank you for reading. Thank you!