gin_ gorm

One 、 Use form

1、 introduce gorm package

import "github.com/jinzhu/gorm"

2、 Import database driver

import _ "github.com/go-sql-driver/mysql"

 For convenience, remember the import path ,GORM Packed some drives ：
import _ "github.com/jinzhu/gorm/dialects/mysql"
// import _ "github.com/jinzhu/gorm/dialects/postgres"
// import _ "github.com/jinzhu/gorm/dialects/sqlite"
// import _ "github.com/jinzhu/gorm/dialects/mssql"
 So it can be used in the following two forms mysql:
1、
import (
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mysql"
)
2、
import (
	"github.com/jinzhu/gorm"
	_ "github.com/go-sql-driver/mysql"
)

3、 Connect to database

//  Connect to database 
	  user name : password @tcp(ip:port)/ database ?charset=utf8&parseTime=True&loc=Local
	db, err := gorm.Open("mysql", "root:[email protected](localhost:3306)/go_project?charset=utf8&parseTime=True&loc=Local")

	if err != nil {
		panic(err)
	}
	defer db.Close() //  Close idle connections 

4.DDL operation

type User struct {
    Id int
    Name string
    Age int
}


//  Create table 
db.Table("user").CreateTable(&User{})   //  Specified table name 

db.CreateTable(&User{})                 //  Do not specify a table name , The model will be followed by s

DML operation

// 1.  increase 
	//db.Create(&models.User{Name: " Li Si ", Age: 18, Addr: "xxx", Pic: "/static/upload/pic.png", Phone: "123456789"})

	// Inquire about 
	var user models.User
	//db.First(&user, 1) //  Default id
	//db.First(&user, "name=?", " Zhang San ") //  //  Specified field 
	//fmt.Println(user)

	//  to update 
	//db.First(&user, 1)
	//db.Model(&user).Update("age", 22)
	//db.Model(&user).Update("addr", "zs-xxxx")

	//  Delete 
	db.First(&user, 2)
	db.Delete(&user)

Model definition

Used for database data conversion and automatic table creation

Mapping relationship between model name and table name

1. The rules
   • The first capital letter becomes lowercase ,
   • Encounter other uppercase letters that become lowercase and preceded by an underscore ,
   • Several capital letters connected , Only the first one follows the above two rules , Other uppercase letters are converted to lowercase , No underline , Lowercase encountered , The first uppercase letter in front becomes lowercase and underlined
   • Plural form
2. give an example
   • User --> users Initial lowercase , The plural
   • UserInfo --> user_infos
   • DBUserInfo --> db_user_infos
   • DBXXXXUserInfo --> dbxxxx_user_infos

Add other rules to the default table name

//  Add sys_ Prefix 

gorm.DefaultTableNameHandler = func (db *gorm.DB, defaultTableName string) string  {
    return "sys_" + defaultTableName;
}


 Custom table name ：
func ( Model ) TableName() string{
    return " New table name "
}


package models

import "github.com/jinzhu/gorm"

type GormModel struct {
	gorm.Model
	Name string
}

func (GormModel) TableName() string {
	return "test_gorm_model"
}

Rules for the correspondence between structure field names and column names

1. The rules * The column name is the serpentine lowercase of the field name
2. give an example
   • Name --> name
   • CreatedTime --> create_time
3. Can pass gorm Label specifies the column name ,AnimalId int64 `gorm:"column:beast_id"`

gorm.Model

Basic model definition gorm.Model, Including field ID,CreatedAt,UpdatedAt,DeletedAt

You just need to specify... In your own model gorm.Model Anonymous field , You can use the four fields above

//  Add fields  `ID`, `CreatedAt`, `UpdatedAt`, `DeletedAt`
type User struct {
    gorm.Model
    Name string
}

ID： The primary key grows by itself

CreatedAt： Used to store the creation time of the record

UpdatedAt： The modification time used to store the record

DeletedAt： Delete time used to store records

Structural tag gorm Use  

type UserInfo struct {
    Id int `gorm:"primary_key"`
    Name string `gorm:"index"`
    Age int 
}

gorm Tag attribute value

• -： Ignore , Do not map this field `gorm:"-"`
• primary_key： Primary key `gorm:"primary_key"`
• AUTO_INCREMENT： Self increasing `gorm:"AUTO_INCREMENT"`
• not null： Not empty , The default is empty. `gorm:"not null"`
• index： Indexes , `gorm:"index"`
  • Create an index and name ： `gorm:"index:idx_name_code"`
• • Optimized query , The equivalent of a catalogue of books

• unique_index: unique index `gorm:"unique_index"`

• unique： only `gorm:"unique"`

• column： Specifies the column name `gorm:"column:user_name"`

• size： String length , The default is 255 `gorm:"size:64"`

• type： Set up sql type `gorm:"type:varchar(100)"` // It is not recommended to change the type directly
• default `default:'galeone'` The default value is

Multiple attribute values are separated by semicolons ( In English, ;):`gorm:"size:64;not null"`

  one-on-one

package relate_tables

//  one-on-one 
type User struct {
	Id   int
	Name string
	Age  int
	Addr string
}

type UserProfile struct {
	Id     int
	Pic    string
	CPic   string
	Phone  string
	User   User //  Connections 
	UserID int
}

 

//  one-on-one 
//  Belong to 
type User struct {
	Id   int
	Name string
	Age  int
	Addr string
}

type UserProfile struct {
	Id    int
	Pic   string
	CPic  string
	Phone string
	//User   User //  Connections 
	User User `gorm:"ForeignKey:UId;AssociationForeignKey:Id"` //  Connections 
	//UserID int //  Default associated fields 
	UId int //uid
}

  contain

//  contain 

type User struct {
	Id int
	Name string
	Age int
	Addr string
	PId int

}


type UserProfile struct {
	Id int
	Pic string
	CPic string
	Phone string
	User User `gorm:"ForeignKey:PId;AssociationForeignKey:Id"`  //  Connections 

}

 

  One to many

//  One to many 

type User2 struct {
	Id int
	Name string
	Age int
	Addr string
	Articles []Article `gorm:"ForeignKey:UId;AssociationForeignKey:Id"`
}

type Article struct {
	Id int
	Title string
	Content string
	Desc string
	//  Foreign keys 
	UId int
}

 

  Many to many

type Article2 struct {
        AId int `gorm:"primary_key:true"`
        Title string
        Content string
        Desc string
        Tags []Tag `gorm:"many2many:Article2s2Tags"`  // ;ForeignKey:AId;AssociationForeignKey:TId

    }

    type Tag struct {
        TId int `gorm:"primary_key:true"`
        Name string
        Desc string
    }

 

 

  One on one operation