Declaring Models

Models are usually just normal Golang structs, basic Go types, or pointers of them. sql.Scanner and driver.Valuer interfaces are also supported.

Model Example:

type User struct {
  gorm.Model
  Name         string
  Age          sql.NullInt64
  Birthday     *time.Time
  Email        string  `gorm:"type:varchar(100);unique_index"`
  Role         string  `gorm:"size:255"` // set field size to 255
  MemberNumber *string `gorm:"unique;not null"` // set member number to unique and not null
  Num          int     `gorm:"AUTO_INCREMENT"` // set num to auto incrementable
  Address      string  `gorm:"index:addr"` // create index with name `addr` for address
  IgnoreMe     int     `gorm:"-"` // ignore this field
}

Struct tags

Tags are optional to use when declaring models. GORM supports the following tags:

Supported Struct tags

Tag	Description
Column	Specifies column name
Type	Specifies column data type
Size	Specifies column size, default 255
PRIMARY_KEY	Specifies column as primary key
UNIQUE	Specifies column as unique
DEFAULT	Specifies column default value
PRECISION	Specifies column precision
NOT NULL	Specifies column as NOT NULL
AUTO_INCREMENT	Specifies column auto incrementable or not
INDEX	Create index with or without name, same name creates composite indexes
UNIQUE_INDEX	Like `INDEX`, create unique index
EMBEDDED	Set struct as embedded
EMBEDDED_PREFIX	Set embedded struct’s prefix name
-	Ignore this fields

Struct tags for Associations

Check out the Associations section for details

Tag	Description
MANY2MANY	Specifies join table name
FOREIGNKEY	Specifies foreign key
ASSOCIATION_FOREIGNKEY	Specifies association foreign key
POLYMORPHIC	Specifies polymorphic type
POLYMORPHIC_VALUE	Specifies polymorphic value
JOINTABLE_FOREIGNKEY	Specifies foreign key of jointable
ASSOCIATION_JOINTABLE_FOREIGNKEY	Specifies association foreign key of jointable
SAVE_ASSOCIATIONS	AutoSave associations or not
ASSOCIATION_AUTOUPDATE	AutoUpdate associations or not
ASSOCIATION_AUTOCREATE	AutoCreate associations or not
ASSOCIATION_SAVE_REFERENCE	AutoSave associations reference or not
PRELOAD	Auto Preload associations or not