How correctly create ForeignKey in GORM | Golang application? - postgresql

Question

In PostgreSQL database I have 2 table:
CREATE TABLE WIDGET_TYPE(
WIDGET_TYPE_ID SERIAL PRIMARY KEY NOT NULL,
WIDGET_TYPE_NAME VARCHAR NOT NULL UNIQUE
);
CREATE TABLE QUESTION(
QUESTION_ID SERIAL PRIMARY KEY NOT NULL,
QUESTION_TEXT TEXT NOT NULL UNIQUE,
WIDGET_TYPE_ID INT NOT NULL,
FOREIGN KEY (WIDGET_TYPE_ID) REFERENCES WIDGET_TYPE (WIDGET_TYPE_ID)
);
As you can see each question has only one widget type for offerend answers.
After that step I am trying to design models in Golang application. I use GORM library for this task. I have problem when try to create new entry in question table. In the body of the POST request I send JSON object:
{
"question_text": "NEW QUESTION TEXT HERE",
"widget_type_id": 2
}
ERROR:
pq: insert or update on table "question" violates foreign key constraint "question_widget_type_id_fkey"
models.go:
package models
type WidgetType struct {
WidgetTypeID int `gorm:"primary_key" json:"widget_type_id"`
WidgetTypeName string `gorm:"not null;unique" json:"widget_type_name"`
}
func (WidgetType) TableName() string {
return "widget_type"
}
type Question struct {
QuestionID int `gorm:"primary_key" json:"question_id"`
QuestionText string `gorm:"not null;unique" json:"question_text"`
WidgetType WidgetType `gorm:"foreignkey:WidgetTypeID"`
WidgetTypeID uint
}
func (Question) TableName() string {
return "question"
}
handlers.go:
var CreateQuestion = func(responseWriter http.ResponseWriter, request *http.Request) {
question := models.Question{}
decoder := json.NewDecoder(request.Body)
if err := decoder.Decode(&question); err != nil {
utils.ResponseWithError(responseWriter, http.StatusBadRequest, err.Error())
return
}
defer request.Body.Close()
if err := database.DBGORM.Save(&question).Error; err != nil {
utils.ResponseWithError(responseWriter, http.StatusInternalServerError, err.Error())
return
}
utils.ResponseWithSuccess(responseWriter, http.StatusCreated, "The new entry successfully created.")
}
Where I make mistake?
I add built-in logger support of GORM. In console it show me next SQL statement:
INSERT INTO "question" ("question_text","widget_type_id") VALUES ('NEW QUESTION TEXT HERE',0) RETURNING "question"."question_id"
As you can see widget_type_id value 0. WHY?