Invalid fields of structure found during automatic migration

Question content

When I try to automatically migrate the table according to my structure, I get this error, I don't know why I get this error

failed to parse value &models.model{id:0x0, createdat:time.date(1,
time.january, 1, 0, 0, 0, 0, time.utc), updatedat:time.date(1,
time.january, 1, 0, 0, 0, 0, time.utc), deletedat:,
dogdata:[]models.dogdata(nil)}, got error invalid field found for
struct github.com/dog-page/models.model's field dogdata: define a
valid foreign key for relations or implement the valuer/scanner
interface

I am new to golang language and gorm, especially when it comes to creating structures for raw json data, here is my intention of using gorm's structure:

type Model struct {
    ID        uint       `gorm:"primarykey:id" json:"id:_id"`
    CreatedAt time.Time  `gorm:"column:created_at" json:"created_at"`
    UpdatedAt time.Time  `gorm:"column:updated_at" json:"updated_at"`
    DeletedAt *time.Time `gorm:"column:deleted_at" json:"deleted_at"`
    DogData   []DogData
}

type DogData struct {
    DogDataID    uint
    Name         string         `json:"name"`
    Life_Span    string         `json:"life_span"`
    Temperaments string         `json:"temperament"`
    Weight       datatypes.JSON `json:"weight"`
    Height       datatypes.JSON `json:"height"`
    Image        datatypes.JSON `json:"image"`
}

type Weight struct {
    Imperial string `json:"imperial"`
    Metric   string `json:"metric"`
}

type Height struct {
    Imperial string `json:"imperial"`
    Metric   string `json:"metric"`
}

type Image struct {
    URL string `json:"url"`
}

Solution

Model’s fields dogdata: Define valid foreign keys for relationships

The model has a one-to-many relationship with dogdata, and gorm cannot recognize foreign keys.

You need to specify the column to store model.id in dogdata (gorm looks for modelid by default),

type model struct {
    id        uint       `gorm:"primarykey:id" json:"id:_id"`
...
    dogdata []dogdata
}

type dogdata struct {
    modelid      uint
    dogdataid    uint
...
}
//create table `dog_data` (`model_id` integer,`dog_data_id` integer,`name` text,`life_span` text,`temperaments` text,constraint `fk_models_dog_data` foreign key (`model_id`) references `models`(`id`))

Or if you want to use another column instead of specifying the column using foreignkey tag

type model struct {
    id        uint       `gorm:"primarykey:id" json:"id:_id"`
...
    dogdata   []dogdata  `gorm:"foreignkey:dogdataid"`

}

type dogdata struct {
    dogdataid    uint
...
}

//create table `dog_data` (`model_id` integer,`dog_data_id` integer,`name` text,`life_span` text,`temperaments` text,constraint `fk_models_dog_data` foreign key (`dog_data_id`) references `models`(`id`))

Not sure about the use case, but I think dogdata can be simplified to, removing the model structure entirely since it is the same as gorm.model

type DogData struct {
    gorm.Model
    Name         string         `json:"name"`
    ...
}

The above is the detailed content of Invalid fields of structure found during automatic migration. For more information, please follow other related articles on the PHP Chinese website!