如何删除关联(多对多)?

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英文:

How to delete association (many2many)?

问题

奇怪的行为发生在删除关联时。
查询生成了一个额外的条件,我没有添加。

type Client struct {
	gorm.Model
	Name        string      `gorm:"unique;not null" validate:"required,min=1,max=30"`
	Kyc_status  string      `gorm:"not null" validate:"required,min=1,max=30"`
	Kyc_remarks string      `gorm:"default:null" validate:"omitempty,min=0,max=200"`
	Operators   []*Operator `gorm:"many2many:client_operators;"`
	Op_ids      []string    `gorm:"-:all" validate:"omitempty,dive,numeric"` // 占位字段,不会成为表的一部分
}
type Operator struct {
	gorm.Model
	Title       string    `gorm:"unique;not null" validate:"required,min=1,max=100"`
	Email       string    `gorm:"not null" validate:"required,email"`
	Mobile      string    `gorm:"not null" validate:"required,min=7,max=15,numeric"`
	Last_online time.Time `gorm:"default:null" validate:"omitempty"`
	Last_ip     string    `gorm:"default:null" validate:"omitempty,ip"`
	Clients     []*Client `gorm:"many2many:client_operators;"`
	Cli_ids     []string  `gorm:"-:all" validate:"omitempty,dive,numeric"`
}

// 查找与客户相关的运营商
var client_query *Client
DBconnection.Where("id = ?", pk).Preload("Operators").First(&client_query)

// 删除与客户相关的运营商
DBconnection.Model(&Client{}).Where("client_id = ?", pk).Association("Operators").Delete(&client_query.Operators)

我期望的删除操作是:

[2.000ms] [rows:0] DELETE FROM client_operators WHERE client_id = 5 AND client_operators.operator_id = 1

或者

[2.000ms] [rows:0] DELETE FROM client_operators WHERE client_operators.client_id = 5 AND client_operators.operator_id = 1

但实际上它执行的是:

[2.000ms] [rows:0] DELETE FROM client_operators WHERE client_id = 5 AND client_operators.client_id IN (NULL) AND client_operators.operator_id = 1

它添加了额外的条件 " AND client_operators.client_id IN (NULL) "。

我尝试了 Association().Clear(),但也没有起作用。

英文:

Strange behaviour deleting association happened.
The query generated an extra condition which i did not add.

type Client struct {
	gorm.Model
	Name        string      `gorm:"unique;not null" validate:"required,min=1,max=30"`
	Kyc_status  string      `gorm:"not null" validate:"required,min=1,max=30"`
	Kyc_remarks string      `gorm:"default:null" validate:"omitempty,min=0,max=200"`
	Operators   []*Operator `gorm:"many2many:client_operators;"`
	Op_ids      []string    `gorm:"-:all" validate:"omitempty,dive,numeric"` // placeholder field, wont be part of table
}
type Operator struct {
	gorm.Model
	Title       string    `gorm:"unique;not null" validate:"required,min=1,max=100"`
	Email       string    `gorm:"not null" validate:"required,email"`
	Mobile      string    `gorm:"not null" validate:"required,min=7,max=15,numeric"`
	Last_online time.Time `gorm:"default:null" validate:"omitempty"`
	Last_ip     string    `gorm:"default:null" validate:"omitempty,ip"`
	Clients     []*Client `gorm:"many2many:client_operators;"`
	Cli_ids     []string  `gorm:"-:all" validate:"omitempty,dive,numeric"`
}

// find operators related to client
var client_query *Client
DBconnection.Where("id = ?", pk).Preload("Operators").First(&client_query)

// delete operators related to client
DBconnection.Model(&Client{}).Where("client_id = ?", pk).Association("Operators").Delete(&client_query.Operators)

I expect the deletion to be:

[2.000ms] [rows:0] DELETE FROM `client_operators` WHERE client_id = 5 AND `client_operators`.`operator_id` = 1

OR

[2.000ms] [rows:0] DELETE FROM `client_operators` WHERE `client_operators`.`client_id` = 5 AND `client_operators`.`operator_id` = 1

However it currently does:

[2.000ms] [rows:0] DELETE FROM `client_operators` WHERE client_id = 5 AND `client_operators`.`client_id` IN (NULL) AND `client_operators`.`operator_id` = 1

It adds the extra condition of " AND `client_operators`.`client_id` IN (NULL) "

I tried Association().Clear() and did not do anything too.

答案1

得分: 1

这是因为你将&Client{}传递给了Model

根据gorm文档,你需要首先构建一个具有有效Id的客户端,像这样:

type Client struct {
    gorm.Model
    Name        string      `gorm:"unique;not null" validate:"required,min=1,max=30"`
    Kyc_status  string      `gorm:"not null" validate:"required,min=1,max=30"`
    Kyc_remarks string      `gorm:"default:null" validate:"omitempty,min=0,max=200"`
    Operators   []*Operator `gorm:"many2many:client_operators;"`
    Op_ids      []string    `gorm:"-:all" validate:"omitempty,dive,numeric"` // 占位字段,不会成为表的一部分
}
type Operator struct {
    gorm.Model
    Title       string    `gorm:"unique;not null" validate:"required,min=1,max=100"`
    Email       string    `gorm:"not null" validate:"required,email"`
    Mobile      string    `gorm:"not null" validate:"required,min=7,max=15,numeric"`
    Last_online time.Time `gorm:"default:null" validate:"omitempty"`
    Last_ip     string    `gorm:"default:null" validate:"omitempty,ip"`
    Clients     []*Client `gorm:"many2many:client_operators;"`
    Cli_ids     []string  `gorm:"-:all" validate:"omitempty,dive,numeric"`
}

// 查找与客户端相关的运营商
var client_query *Client
DBconnection.Where("id = ?", pk).Preload("Operators").First(&client_query)



// 删除与客户端相关的运营商
DBconnection.Model(&Client{ID: pk}).Association("Operators").Delete(&client_query.Operators)

英文:

This is happening because you're passing &Client{} to Model.

Looking at gorm docs you need to construct a client with a valid Id first like this:

type Client struct {
    gorm.Model
    Name        string      `gorm:"unique;not null" validate:"required,min=1,max=30"`
    Kyc_status  string      `gorm:"not null" validate:"required,min=1,max=30"`
    Kyc_remarks string      `gorm:"default:null" validate:"omitempty,min=0,max=200"`
    Operators   []*Operator `gorm:"many2many:client_operators;"`
    Op_ids      []string    `gorm:"-:all" validate:"omitempty,dive,numeric"` // placeholder field, wont be part of table
}
type Operator struct {
    gorm.Model
    Title       string    `gorm:"unique;not null" validate:"required,min=1,max=100"`
    Email       string    `gorm:"not null" validate:"required,email"`
    Mobile      string    `gorm:"not null" validate:"required,min=7,max=15,numeric"`
    Last_online time.Time `gorm:"default:null" validate:"omitempty"`
    Last_ip     string    `gorm:"default:null" validate:"omitempty,ip"`
    Clients     []*Client `gorm:"many2many:client_operators;"`
    Cli_ids     []string  `gorm:"-:all" validate:"omitempty,dive,numeric"`
}

// find operators related to client
var client_query *Client
DBconnection.Where("id = ?", pk).Preload("Operators").First(&client_query)



// delete operators related to client
DBconnection.Model(&Client{ID: pk}).Association("Operators").Delete(&client_query.Operators)

huangapple
  • 本文由 发表于 2022年3月22日 18:21:06
  • 转载请务必保留本文链接:https://go.coder-hub.com/71570355.html
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