db.Model(&Usertable).Create(data): How to pass the correct table name?

When using Golang for database operations, we often use code like `db.Model(&Usertable).Create(data)` to create new data. However, sometimes we may encounter a problem: how to pass the correct table name? In this article, PHP editor Youzi will answer this question in detail to help readers better understand how to correctly pass the table name for smooth database operations.

Question content

I am trying to insert a row into a table defined as a model. The following are relevant code snippets:

Package structure:

gorm
|- server
   |- insertRow.go
|- pkg
   |- models
      |- mytable.go
   |- database
      | - connectdb.go

mytable.go：

package models

type Usertable struct {
    Firstname    string `gorm:"column:firstname"`
    Lastname  string `gorm:"column:lastname"`
}

func (fmap *Usertable) TableName() string { return "usertable" }

insertRow.go

package main
import (
        "fmt"
       "gorm/pkg/models"
        "gorm/pkg/database"
)

func  main() {
  params := map[string]interface{} {
        "Firstname" : "MyFirstName",
        "Lastname" : "LastName" ,
 }
        db, _ := database.NewStorage("postgres", "testdb")

        var user models.Usertable

        err := db.DB.Debug().Model(&user).Create(params)
        if err != nil {
                fmt.Println("Error :=", err)
        } else {
                fmt.Println("Success")
        }

}

Table definition:

testdb=# \d+ usertable
                                 Table "public.usertable"
  Column   | Type | Collation | Nullable | Default | Storage  | Stats target | Description
-----------+------+-----------+----------+---------+----------+--------------+-------------
 firstname | text |           |          |         | extended |              |
 lastname  | text |           |          |         | extended |              |

The following error will occur when executing insertRow.go:

(/root/gorm/cloudOps/server/testDB/insertRow.go:17)
[2023-09-23 23:51:26]  pq: zero-length delimited identifier at or near """"

(/root/gorm/cloudOps/server/testDB/insertRow.go:17)
[2023-09-23 23:51:26]  [0.45ms]  **INSERT INTO "" DEFAULT VALUES RETURNING "".***
[0 rows affected or returned ]
Error := &{{{0 0} 0 0 {{} 0} {{} 0}} map[Firstname:MyFirstName Lastname:LastName] pq: zero-length delimited identifier at or near """" 0 0xc0000a4b60 false 2 {0xc0001a3d60} 0xc0001e8420 {{0 0} {[] {} 0xc00021cc20} map[] 0} 0xc0000a4c30 <nil> 0xc0000a2c78 false <nil>}

The table name in the insert command seems to be empty, please let me know what is wrong with my insert command and how can I pass the correct table name to the Create call.

I also tried it, with the same result:

package main
import (
    "fmt"
//       "gorm/pkg/models"
    "gorm/pkg/database"
    "gorm.io/gorm"
)

type Usertable struct {
    gorm.Model
    Firstname    string `gorm:"column:firstname"`
    Lastname  string `gorm:"column:lastname"`
}

func  main() {
  params := map[string]interface{} {
    "Firstname" : "MyFirstName",
    "Lastname" : "LastName" ,
 }
    db, _ := database.NewStorage("postgres", "testdb")


    err := db.DB.Debug().Model(&Usertable{}).Create(params)
    if err != nil {
        fmt.Println("Error :=", err)
    } else {
        fmt.Println("Success")
    }

}

Workaround

You set up a map[string]interface{} to insert, but gorm expects to be passed a structure

user := models.Usertable{
    Firstname: "MyFirstName",
    Lastname:  "LastName",
}

result := db.DB.Debug().Create(&user)

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