support postgres varchar(N)/Char(N) for primary keys about gorm HOT 4 CLOSED

I will consider in future.

But if you choose char as primary key. then you can't search with db.First(&user, 123) anymore. so don't think it is really helpful for me.

For now, I suggest you just ignore the Id column, and use another field as the primary key.

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Add my answer here for a reddit user's question for those users who may interested about this issue.

Could I use uuid (string) as primary key?

No, this is not supported, if so, you will lose the ability to search with primary key. for example:

db.First(&User{}, "blalalalalalaaa")
// db.First(&User{}, 12)
// db.First(&User{}, "age = 20")

We can't know the word "blalalalalalaaa" is sql or primary key. if you want uuid, suggest you could do it like this:

type User struct {
  id int64
  uuid string
}

Then you won't lose the ability to search with primary key. also quite convenient to search with uuid by doing this:

// Find record
db.Where("uuid = ?", "xxxx").First(&User{})

// Find the user, and update some columns
// If not found, then create the record with those attributes
db.Where(User{Uuid: "xxxx"}).Assign("age", 99).FirstOrCreate(&User{})

// Find the user and update some columns
// If not found, initialize the struct with those attributes
db.Where(User{Uuid: "xxxx"}).Assign(User{Age: 99, Email: "[email protected]"}).FirstOrInit(&User{})

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Hi jinzhu!
Thank you for answer.

Actually, the question about string as primary key is mostly about database design approach. To support natural primary keys or do not at atll. I believe using natural primary keys reasonable in some cases. It makes design simplier. As instance:

type Currency struct {
Id string
Name string
Symbol string
}

type CustomerAccount struct {
Id int64
CurrencyId string
Balance float64
...
}

usd := &Currency{Id : "USD", Name: "USA dollar", Symbol: "$"}

ca := &{CurrrencyId : "USD", Balance : 100}

Anyway, the library is your child, your rules :)

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type Currency struct {
  Id         int64
  Code    string
  Name   string
  Symbol string
}

type CustomerAccount struct {
  Id                   int64
  CurrencyCode string
  Balance          float64
}

For me, I prefer write it like this. but anyway, I will look it back after finish other features like indexes, validations, customizable sql type, scopes...

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