How does the type interface work with GORM?

Question

I have an interface type named Invoice :

type Invoice interface {
    GetTransactions() ([]Transaction, error)
}

type DebitInvoice struct { 
    gorm.Model
    ClientID uint  `json:"client_id"`
    Client   Store `json:"client"`
    Debt     uint  `json:"debt"` //REMAINING PAYMENT
}

func (d DebitInvoice) GetTransactions() ([]Transaction, error) {
    // process
    return transactions, nil
}

type CreditInvoice struct { //PEMBELIAN
    gorm.Model
    InvoiceCreditID string `json:"invoice_credit_id"`
    StoreID         uint   `json:"store_id"`
    Store           Store  `json:"store"`
    Debt            uint   `json:"debt"` //REMAINING PAYMENT
}

func (c CreditInvoice) GetTransactions() ([]Transaction, error) {
    // process
    return transactions, nil
}

as you can see, the DebitInvoice and CreditInvoice are Invoice because it implements GetTransactions()([]Transactions, error).

and I have this kind of model (in struct) where we are using Invoice interface as one of the field

type Transaction struct {
    gorm.Model
    InventoryID uint      `json:"inventory_id"`
    Inventory   Inventory `json:"inventory"`
    InvoiceID   uint      `json:"invoice_id"`
    InvoiceType string    `json:"invoice_type"` //Credit/Debit (Out/In)
    Invoice     Invoice   `json:"invoice"`
    TotalPrice  uint      `json:"total_price"`
    Discount    uint      `json:"discount"`
}

But when I migrate this with GORM AutoMigrate. It doesn't work, it shows unsupported data type: program_akuntansi/models.Invoice and the transactions table is not created

My expectations with Transaction model is :

• Invoice field will create a new record to their respective table
• InvoiceType field is the name of table that invoice created
• InvoiceID field is the ID of the record in InvoiceType table

but none of it doesn't work

So back to my question, how does the Interface Type work with GORM and how do I fix my code?