How to Create or Update a record with GORM?

问题

Gorm has a FirstOrCreate method and a FirstOrInit but how to check afterwards if the record was actually created? I like to create a record if it does not exists and if it exists I want to update some fields.

回答1:

gormDB.Where(entity.AggregatedData{Type: v.Type}).Assign(entity.AggregatedData{Type: v.Type, Data: v.Data}).FirstOrCreate(v)


 SELECT * FROM "aggregated_data"  WHERE ("aggregated_data"."type" = '2') ORDER BY "aggregated_data"."id" ASC LIMIT 1

and if exist then

 UPDATE "aggregated_data" SET "data" = '[{"a":2}]', "type" = '2'  WHERE "aggregated_data"."id" = '2' AND (("aggregated_data"."type" = '2'))

else

INSERT INTO "aggregated_data" ("data","type") VALUES ('[{"a":2}]','1') RETURNING "aggregated_data"."id"

回答2:

See Attrs here. It won't exactly tell you whether the record was actually created, but will let you update some fields only if record was actually created (which seems to be what you want to achieve in the end).

回答3:

FirstOrInit and FirstOrCreate are different. If there is no match record in database, FirstOrInit will init struct but not create record, FirstOrCreate will create a record and query that record to struct.

So let's back to you question. How to update or create?

The answer

var user User
if err := db.Where("name = ?", "xxxx").First(&user).Error; err != nil {
    // error handling...
    if gorm.IsRecordNotFoundError(err){
        db.Create(&newUser)  // newUser not user
    }
}else{
    db.Model(&user).Where("id = ?", 3333).Update("name", "nick")
}

回答4:

Here's example from gorm documentation CRUD section

user := User{Name: "Jinzhu", Age: 18, Birthday: time.Now()}

db.NewRecord(user) // => returns `true` as primary key is blank

db.Create(&user)

db.NewRecord(user) // => return `false` after `user` created

来源：https://stackoverflow.com/questions/39333102/how-to-create-or-update-a-record-with-gorm

标签

orm

go-gorm