Dynamically initialize a struct given an array of strings

Question

I am using gorm to query and manage mysql. The function named SyncDB in the following snippet migrates the latest user schema found in the user.go file under schema directory.

    package db

    import (
       "my-server/db/schema"
       "github.com/jinzhu/gorm"
    )

    func SyncDB(db *gorm.DB) {

        db.AutoMigrate(&schema.User{})

    }

I have multiple files under the schema directory. I tried reading all the file names under the directory schema and have the filenames as an array which looks like:

filenames := []string{
   "user.go",
   "password.go",
   "profile.go",
}

Is there a way to use filenames array and dynamically call:

db.AutoMigrate(&schema.User{})

For example, &schema.User{} gets replaced by &schema.Password{} in the next call. How could I make this thing dynamic?

Definitely there is no way with `GORM` (I could find any documentation) but the question if we could do this with `GO`? — Suhail Gupta, Jan 21 '20 at 08:09
You can't get types (or values of those types) by their `string` names. — icza, Jan 21 '20 at 08:11
@icza `AutoMigrate` accepts the interface type. Could we utilize the behavior? — Suhail Gupta, Jan 21 '20 at 08:49
No, you need to pass values of your type (or pointers), and that you cannot get just by their string names in Go. — icza, Jan 21 '20 at 09:03
There is [type assertion](https://golang.org/ref/spec#Type_assertions) and type [conversion](https://golang.org/ref/spec#Conversions). — icza, Jan 21 '20 at 09:16

score 0 · Answer 1 · answered Jan 21 '20 at 07:58

0

There is not way to send the file. I would suggest to create slice of struct and pass that into AutoMigrate as mentioned below:

values := []interface{}{&schema.User{}, &profile.Profile{}, &password.Password{}}

if err := DB.AutoMigrate(values...).Error; err != nil {
    panic(fmt.Sprintf("No error should happen when create table, but got %+v", err))
}

answered Jan 21 '20 at 07:58

Prakash Kumar

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This is no different from directly passing to `AutoMigrate`. This does not have a solution with `gorm` but the question is if there is a way with `go`. – Suhail Gupta Jan 21 '20 at 08:01

Dynamically initialize a struct given an array of strings

1 Answers1