Does Go Gorm provide any method to auto map existing tables in Mysql database

I am a newcomer to Go. I have an old tool to check and compare data in the Mysql database to my device, and I want to rewrite the tool in Go.

Since the tables and data have been already in the Mysql, I try to use GORM to auto map the existing tables. But I am not sure how to do that? I did not find any description of automapping an existing table in the GORM documentation.

I redeclare the existing table model and try to query data. The procedure is as below:

For example one of my tables is like this:

MariaDB [neutron]> desc lbaas_loadbalancers;
+---------------------+--------------+------+-----+---------+-------+
| Field               | Type         | Null | Key | Default | Extra |
+---------------------+--------------+------+-----+---------+-------+
| project_id          | varchar(255) | YES  | MUL | NULL    |       |
| id                  | varchar(36)  | NO   | PRI | NULL    |       |
| name                | varchar(255) | YES  |     | NULL    |       |
| description         | varchar(255) | YES  |     | NULL    |       |
| vip_port_id         | varchar(36)  | YES  | MUL | NULL    |       |
| vip_subnet_id       | varchar(36)  | NO   |     | NULL    |       |
| vip_address         | varchar(36)  | YES  |     | NULL    |       |
| admin_state_up      | tinyint(1)   | NO   |     | NULL    |       |
| provisioning_status | varchar(16)  | NO   |     | NULL    |       |
| operating_status    | varchar(16)  | NO   |     | NULL    |       |
| flavor_id           | varchar(36)  | YES  | MUL | NULL    |       |
+---------------------+--------------+------+-----+---------+-------+
11 rows in set (0.002 sec)

MariaDB [neutron]> select * from lbaas_loadbalancers \G;
*************************** 1. row ***************************
         project_id: 346052548d924ee095b3c2a4f05244ac
                 id: f6638d02-29f8-41aa-9433-179bf49f5fbd
               name: test1
        description:
        vip_port_id: 21cebbd5-fa4c-4d20-9858-d14ba3eacea8
      vip_subnet_id: 0916f471-afcd-48ee-afc5-56bcb0efa963
        vip_address: 172.168.1.6
     admin_state_up: 1
provisioning_status: ACTIVE
   operating_status: ONLINE
          flavor_id: NULL
1 row in set (0.003 sec)

Then I try to use GORM mapping the table. I just chosen two fields ID and Name for the test.

package main

import (
	"log"

	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

// declare only two attribute in the model for test purpose 
type Lbaas_loadbalancers struct {
	ID   string
	Name string
}

func main() {
	var lb Lbaas_loadbalancers
	dsn := "test:test@tcp(192.168.0.17:3306)/test?charset=utf8mb4&parseTime=True&loc=Local"
	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Fatal("connection error")
	}

	test := db.Take(&lb)
	log.Println("test err is ", test.Error)
	log.Println(test.RowsAffected)

    // this line report error: ./db.go:25:6: test.ID undefined (type *gorm.DB has no field or method ID)
	log.Println(test.ID)
    
    // if I comment the above line, this print out 'mysql', but the actual name is 'test1'.
	log.Println(test.Name())
}

Finally, I run go run db.go, I got this error:

➜  test git:(main) ✗ go run db.go
# command-line-arguments
./db.go:27:20: cannot convert test.Config.Dialector.Name (type func() string) to type string

It seems not the right way to do it. what is the correct way to auto map an existing database in Mysql by using GORM module?

If the below code is the correct way, why I cannot get the ID attribute from the return value of db.Take method directly? Do I need to do data conversion?

Please give me some hints, thanks.

I know what is wrong here, I should not get ID and Name from the db.Take return, It takes the address of lb variable, and change the lb.

I am so silly, just realized the problem.