How to add auto increment to Go struct with json

huangapple
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英文:

How to add auto increment to Go struct with json

问题

我想在GORM中覆盖Id值字段，因为我还使用json进行编组和解组。

  1. package article
  3. import "github.com/jinzhu/gorm"
  5. type Article struct {
  6.     gorm.Model
  7.     Id          int    `json:"id"`
  8.     Title       string `json:"title"`
  9.     Description string `json:"description"`
  10.     Content     string `json:"content"`
  11. }

我希望像这样添加gorm属性：

  1. `gorm:"default:'galeone'"`

但是它无法编译通过。

  1. package article
  3. import "github.com/jinzhu/gorm"
  5. type Article struct {
  6.     gorm.Model
  7.     Id          uint    `json:"id" sql:"AUTO_INCREMENT" gorm:"primary_key"`
  8.     Title       string `json:"title"`
  9.     Description string `json:"description"`
  10.     Content     string `json:"content"`
  11. }

我正在使用来自这里的Gorm [https://github.com/jinzhu/gorm][1]。

我得到了以下错误：

  1. 2016/12/21 15:17:48 DB Initialized successfully
  3. (duplicate column name: id) 
  4. [2016-12-21 15:17:48]  
  6. (no such table: articles) 
  7. [2016-12-21 15:17:48]

这是我创建数据库的方式，它工作正常，只是想在Article结构上自动递增。

  1. package dbprovider
  3. import (
  4.     "github.com/jinzhu/gorm"
  5.     _ "github.com/jinzhu/gorm/dialects/sqlite"
  6.     "rest/article"
  7.     "log"
  8. )
  10. var db gorm.DB
  12. var isInitialized bool
  14. func InitDb() {
  15.     isInitialized = false
  16.     db, err := gorm.Open("sqlite3", "../../articles.db")
  18.     if (db != nil && err == nil) {
  19.         log.Print("Db Initialized")
  20.         isInitialized = true
  21.     } else {
  22.         isInitialized = false
  23.         defer db.Close()
  24.         log.Panic("DB not initialized")
  25.     }
  26. }
  28. func AddArticle(article *article.Article) {
  29.     if (isInitialized) {
  30.         db.Create(&article)
  31.     }
  32. }
英文:

I want to override Id value field in GORM with since I am using json also to marchal and unmarshall.

  1. package article
  3. import "github.com/jinzhu/gorm"
  5. type Article struct {
  6. 	gorm.Model
  7. 	Id          int    `json:"id"`
  8. 	Title       string `json:"title"`
  9. 	Description string `json:"description"`
  10. 	Content     string `json:"content"`
  11. }

I wish to add gorm property like this

  1. `gorm:"default:'galeone'"`

But it is not compiling

  1. package article
  3. import "github.com/jinzhu/gorm"
  5. type Article struct {
  6. 	gorm.Model
  7. 	Id          uint    `json:"id" sql:"AUTO_INCREMENT" gorm:"primary_key"`
  8. 	Title       string `json:"title"`
  9. 	Description string `json:"description"`
  10. 	Content     string `json:"content"`
  11. }

I am using Gorm from here [https://github.com/jinzhu/gorm][1]

I am getting

  1. 2016/12/21 15:17:48 DB Initialized successfully
  3. (duplicate column name: id) 
  4. [2016-12-21 15:17:48]  
  6. (no such table: articles) 
  7. [2016-12-21 15:17:48]

This is how i am creating DB it is working fine just want auto increment on Article struct

  1. package dbprovider
  3. import (
  4. 	"github.com/jinzhu/gorm"
  5. 	_"github.com/jinzhu/gorm/dialects/sqlite"
  6. 	"rest/article"
  7. 	"log"
  8. )
  10. var db gorm.DB
  12. var isInitialized bool
  14. func InitDb() {
  15. 	isInitialized = false
  16. 	db, err := gorm.Open("sqlite3", "../../articles.db")
  18. 	if (db != nil && err == nil) {
  19. 		log.Print("Db Initialized")
  20. 		isInitialized = true
  21. 	} else {
  22. 		isInitialized = false
  23. 		defer db.Close()
  24. 		log.Panic("DB not initialized")
  25. 	}
  26. }
  28. func AddArticle(article *article.Article) {
  29. 	if (isInitialized) {
  30. 		db.Create(&article)
  31. 	}
  32. }

答案1

得分: 1

首先，根据办公室指南，gorm:"default:'galeone'"是你的字段的默认值。当你没有给出值时，参考gormDefaultValue。所以你的ID字段需要更改，因为你的默认值是字符串，但字段是整数。

  1. Id    int    `json:"id" gorm:"default:1"`

在InitDb函数中，你重新定义了一个变量db。当你编译或运行Go程序时，会出现错误。你需要更改两行代码：

  1. var db gorm.DB -> var db *gorm.DB
  2. func InitDb
  1. func InitDb() {
  2.     isInitialized = false
  3.     //Change below code 
  4.     var err interface{}
  5.     db, err = gorm.Open("sqlite3", "../../articles.db")
  7.     if db != nil && err == nil {
  8.         log.Print("Db Initialized")
  9.         isInitialized = true
  10.     } else {
  11.         isInitialized = false
  12.         defer db.Close()
  13.         log.Panic("DB not initialized")
  14.     }
  15. }
英文:

First. According to Office Guideline
gorm:"default:'galeone'" is your field default value

Refer : gormDefaultValue
when you not give the value.
so your ID field need to be change . because your default value is string
but the field is int

  1. Id    int    `json:"id" gorm:"default:1"`

and on func InitDb. you redefinition a variable db.Will occur error when you compiler or run go program. you need change two line

  1. var db gorm.DB -> var db *gorm.DB
  2. func InitDb
  1. func InitDb() {
  2. isInitialized = false
  3. //Change below code 
  4. var err interface{}
  5. db, err = gorm.Open("sqlite3", "../../articles.db")
  7. if (db != nil && err == nil) {
  8.     log.Print("Db Initialized")
  9.     isInitialized = true
  10. } else {
  11.     isInitialized = false
  12.     defer db.Close()
  13.     log.Panic("DB not initialized")
  14. }

}

huangapple
  • 本文由 发表于 2016年12月21日 15:41:38
  • 转载请务必保留本文链接：https://go.coder-hub.com/41257525.html
  • go
  • go-gorm
  • json
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