Beego framework orm operation exper operation

1. Basic use

1. Initialize a project

2. Install dependent packages

// orm框架
go get github.com/astaxie/beego/orm 
// 使用什么数据库
go get github.com/go-sql-driver/mysql

3. main.goUse initfunctions to connect in

import (
	...
	_ "github.com/go-sql-driver/mysql" // 必须加上
)

func init()  {
      
      
	orm.RegisterDriver("mysql", orm.DRMySQL)
  // default必须要有,表示连接的数据库别名,可能是多个
	orm.RegisterDataBase("default", "mysql", "用户名:密码@tcp(localhost:3306)/数据库名?charset=utf8mb4&parseTime=True&loc=Local")
}

4. Create a modelsfolder to store the data model (one-to-one correspondence with the database table)

package models

import "github.com/astaxie/beego/orm"

type User struct {
      
      
	Id int
	Name string
	Age int
	Address string
}

//自定义表名,可以不写的会默认以下划线来分割驼峰命名的
func (self *User) TableName () string  {
      
      
	return "user"
}

func init() {
      
      
  // 使用exper表达式必须要注入模型,因此我们强制自己不管什么都要在模型中使用init函数来注入模型
	orm.RegisterModel(new(User))
}

Two, `exper`two ways to create a handle using query

1. Use the table name directly to create a handle

type UserExper1Controller struct {
      
      
	beego.Controller
}

func (ctx *UserExper1Controller) Get() {
      
      
	o := orm.NewOrm()
  // 使用表名的方式来创建一个exper查询句柄
	qs :=o.QueryTable("user")
  // 查询后的数据需要放到user这个结构体中
	user := models.User{
      
      }
  // 使用expre表达式查询【name__exact】表示name完全匹配,One表示查询一条数据
	qs.Filter("name__exact", "孙悟空").One(&user)
	fmt.Println(user)
	ctx.TplName="orm.html"
}

2. The way of using data model [recommended to use data model]

type UserExper1Controller struct {
      
      
	beego.Controller
}

func (ctx *UserExper1Controller) Get() {
      
      
	o := orm.NewOrm()
  // 使用数据模型
	userModel := new(models.User)
	qs :=o.QueryTable(userModel)
	user := models.User{
      
      }
	qs.Filter("name__exact", "孙悟空").One(&user)
	fmt.Println(user)
	ctx.TplName="orm.html"
}

Three, common `exper`expression operation symbols

No	name	For example	Compare native SQL
1	`exact/iexact`	`name__exact`(The `name`field is equal to the following)	`where name = "xx"`
2	`contains/icontains`	`name__contains`(contain)	`where name like "%xx%"`
3	`gt/gte`	`age__gt`(Greater than/greater than or equal to)	`where age > 19`
4	`lt/lte`	`age__lt`(Less than/less than or equal to)	`where age < 19`
5	`startswith/istartswith`	`name__startswith`(Start with what)	`where name like "x%"`
6	`endswith/iendswith`	`name__endswith`(Ends with what)	`where name like "%x"`
7	`in`	`age__in`(In what range)	`where age in (1,2,3)`
8	`isnull`	`qs.Filter("gender__isnull",true).One(&user)`

Fourth, `beego`open the method of printing the `orm`corresponding `sql`sentence in

1. Open globally, in main.go(recommended)

func main() {
      
      
	orm.Debug = true
	beego.Run()
}

2. Partial development in the corresponding controller

func (ctx *UserExper1Controller) Get() {
      
      
	// 开始打印对应的sql
	orm.Debug = true
	...
	ctx.TplName="orm.html"
}

Five, `Filter`use

1. Query the desired field

o := orm.NewOrm()
// 使用数据模型
userModel := new(models.User)
qs := o.QueryTable(userModel)
user := models.User{
      
      }
// 需要查询出什么字段就在后面加
qs.Filter("name__exact", "孙悟空").One(&user, "Name","Age")
fmt.Println(user)
ctx.Data["json"] = user
ctx.ServeJSON()

2. Multi-condition query

o := orm.NewOrm()
userModel := new(models.User)
qs := o.QueryTable(userModel)
user := models.User{
      
      }
// 多条件的时候就多使用Filter
qs.Filter("name__exact","孙悟空").Filter("age__gte", 2000).One(&user, "Name","Age")
// 匹配的sql
// select name, age from user where name = "孙悟空" and age >= 2000;
ctx.Data["json"] = user
ctx.ServeJSON()

3. Use allmultiple query statements

o := orm.NewOrm()
userModel := new(models.User)
qs := o.QueryTable(userModel)
//返回多条语句要用切片
user := []models.User{
      
      }
//不加条件的查询
qs.All(&user, "Name", "Age", "Address")
// select name, age, address from user;
ctx.Data["json"] = user
ctx.ServeJSON()

4. Use the Excludeexclude field to return

o := orm.NewOrm()
userModel := new(models.User)
qs := o.QueryTable(userModel)
user := []models.User{
      
      }
qs.Exclude("name__exact", "孙悟空").All(&user)
// select * from user where not name = "孙悟空";
ctx.Data["json"] = user
ctx.ServeJSON()

5. Paging query statement

o := orm.NewOrm()
userModel := new(models.User)
qs := o.QueryTable(userModel)
user := []models.User{
      
      }
//查询3条,从第一条开始查询
qs.Limit(3).Offset(1).All(&user)
// select * from user limit 1,3;
ctx.Data["json"] = user
ctx.ServeJSON()

6. Sort by field

o :=orm.NewOrm()
userModel := new(models.User)
qs := o.QueryTable(userModel)
user := []models.User{
      
      }
// 默认是升序,如果要降序的话就直接OrderBy("-age")
qs.OrderBy("age").All(&user)
ctx.Data["json"] = user
ctx.ServeJSON()

7. Determine whether it exists

exist := qs.Filter("name__exact","猪八戒").Exist()
// 返回true或者false
fmt.Println(exist)

8. Use the Updateupdate operation

o := orm.NewOrm()
userModel := new(models.User)
num, err := o.QueryTable(userModel).Filter("name__exact", "孙悟空").Update(orm.Params{
      
      
  "Age": 2000,
})
fmt.Println(num) // 受影响的行数
fmt.Println(err) // 错误
ctx.Data["json"] = map[string]string{
      
      
  "code":    "0",
  "message": "成功",
}
ctx.ServeJSON()

9, delete statement

o := orm.NewOrm()
userModel := new(models.User)
num, err := o.QueryTable(userModel).Filter("name__exact","孙悟空").Delete()
fmt.Println(num)
fmt.Println(err)

10. PrepareInsertInsert multiple statements at the same time

Be careful to close at the end

o := orm.NewOrm()
users := []models.User{
      
      
  {
      
      Name: "孙悟空",Age: 1000,Address: "花果山"},
  {
      
      Name: "猪八戒",Age: 800,Address: "高老庄"},
  {
      
      Name: "沙增",Age: 500,Address: "流沙河"},
}
inserter, _ := o.QueryTable(new(models.User)).PrepareInsert()
// 循环切片的数据
for _, val := range users {
      
      
  id, err := inserter.Insert(&val)
  fmt.Println(id)
  fmt.Println(err)
}
//注意要记得关闭
inserter.Close()

// 但是插入多条数据建议使用InsertMulti
o := orm.NewOrm()
users := []models.User{
      
      
  {
      
      Name: "郭靖", Age: 30, Address: "襄阳"},
  {
      
      Name: "黄蓉", Age: 23, Address: "襄阳"},
}
num, err := o.InsertMulti(100, &users)
fmt.Println(num, err)

11. valuesUse (really jsonreturn the desired field)

var maps []orm.Params
o := orm.NewOrm()
num, err := o.QueryTable(new(models.User)).Filter("age__gte", 100).Values(&maps, "Name", "Id", "Address", "Age")
fmt.Println(num, err)
ctx.Data["json"] = maps
ctx.ServeJSON()

12. The ValuesListdefault return is 1000 data

var lists []orm.ParamsList
o := orm.NewOrm()
// 返回数组,里面嵌套根据字段嵌套
num, err := o.QueryTable(new(models.User)).ValuesList(&lists, "Name")
fmt.Println(num, err)
ctx.Data["json"] = lists
ctx.ServeJSON()

// 返回的数据结构
[
  [
    "唐三藏"
  ],
  [
    "孙悟空"
  ]
]

13. ValuesFlatFlattening returns an array

var lists orm.ParamsList
o := orm.NewOrm()
// 返回数组,里面嵌套根据字段嵌套
num, err := o.QueryTable(new(models.User)).ValuesFlat(&lists, "Name")
fmt.Println(num, err)
ctx.Data["json"] = lists
ctx.ServeJSON()

// 返回数据
[
  "唐三藏",
  "孙悟空",
]

14. UpdateAdd values based on existing fields

o := orm.NewOrm()
num, err := o.QueryTable(new(models.User)).Filter("name__exact", "孙悟空").Update(orm.Params{
      
      
  "Age": orm.ColValue(orm.ColAdd, 100),
})
// 对应的原生sql
// update user set age=age+100 where name = "孙悟空";
fmt.Println(num, err)

Corresponding other methods are

ColAddAdd to
ColMinuscut back
ColMultiplymultiplication
ColExceptdivision