Models( ClassLevel -> ClassList ->Subject -> PdfResource)

models.go

import "time"


type 	(
ClassLevel struct {
		ID          uint   `gorm:"primaryKey"`
		Number      string `json:"number" gorm:"size:70;unique;not null"`
		Name        string `json:"name" form:"name" binding:"required" gorm:"size:60;unique;not null"`
		LevelPic    string `json:"level_pic" form:"level_pic" binding:"required" gorm:"not null"`
		FileName    string `json:"file_name" form:"file_name" binding:"required" gorm:"size:100;not null"`
		Description string `json:"description" form:"description" binding:"required" gorm:"not null; type:longtext"`
		UserNumber  string `json:"user_number" gorm:"size:70;index;not null"`
		CreatedAt   time.Time
		UpdatedAt   time.Time
		DeletedAt   *time.Time `sql:"index"`
	}

  ClassList struct {
		ID               uint   `gorm:"primaryKey"`
		Number           string `json:"number" gorm:"size:70;unique;not null"`
		Name             string `json:"name" form:"name" binding:"required" gorm:"size:60;unique;not null"`
		UserNumber       string `json:"user_number" gorm:"size:70;index;not null"`
		ClassLevelNumber string `json:"class_level_number" gorm:"not null; index"`
		CreatedAt        time.Time
		UpdatedAt        time.Time
		DeletedAt        *time.Time `sql:"index"`
		ClassLevel       ClassLevel `gorm:"foreignKey:ClassLevelNumber;references:Number"`
	}
  
	Subject struct {
		ID              uint   `gorm:"primaryKey"`
		Number          string `json:"number" gorm:"size:70;unique;not null"`
		Name            string `json:"name" form:"name" binding:"required" gorm:"size:60;unique;not null"`
		UserNumber      string `json:"user_number" gorm:"size:70;index;not null"`
		ClassListNumber string `json:"class_list_number" gorm:"not null; index"`
		CreatedAt       time.Time
		UpdatedAt       time.Time
		DeletedAt       *time.Time `sql:"index"`
		ClassList       ClassList  `gorm:"foreignKey:ClassListNumber;references:Number"`
	}
  
  PdfResource struct {
		ID            uint   `gorm:"primaryKey"`
		Number        string `json:"number" gorm:"size:70;unique;not null"`
		Name          string `json:"name" form:"name" binding:"required" gorm:"size:100;not null"`
		FileName      string `json:"file_name" form:"file_name" binding:"required" gorm:"size:100;not null"`
		UserNumber    string `json:"user_number" gorm:"size:70;index;not null"`
		SubjectNumber string `json:"subject_number" gorm:"not null; index"`
		CreatedAt     time.Time
		UpdatedAt     time.Time
		DeletedAt     *time.Time `sql:"index"`
		Subject       Subject    `gorm:"foreignKey:SubjectNumber;references:Number"`
	}

	
)