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swxc

请问 gorm 如何获取到更新后的值

  •  
  •   swxc · Sep 20, 2020 · 2207 views
    This topic created in 2085 days ago, the information mentioned may be changed or developed.
    type Counter struct {
    	BizName   string `gorm:"primary_key"`
    	NextId    string
    	CreatedAt time.Time
    }
    
    
    counter := model.Counter{BizName: "class"}
    
    err = d.Model(&counter).Update(ctx, "next_id", gorm.Expr("next_id  + ?",1)).Error
    
    

    想实现一个简易的发号器,想利用 mysql update 的原子性,更新 NextId 并获取到更新后的值,请问如何搞定

    4 replies    2020-09-21 18:16:47 +08:00
    wleven
        1
    wleven  
       Sep 21, 2020
    d.Model(&counter).Update(ctx, "next_id", gorm.Expr("next_id + ?",1)).Find(&counter).Error
    crclz
        2
    crclz  
       Sep 21, 2020
    利用 postgresql 的 Returning 关键字。mysql 或者其他估计也有对应的解决方案。
    ghjacky
        3
    ghjacky  
       Sep 21, 2020
    d.Model(&counter).Debug().Update(ctx, "next_id", gorm.Expr("next_id + ?",1))
    xuegj1010
        4
    xuegj1010  
       Sep 21, 2020
    d.Model(&counter).Update(ctx, "next_id", gorm.Expr("next_id + ?",1)).Find(&counter).Scan(&counter).Error
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