Gorm-通过迁移升级列约束

Question

How do you perform a Migration with gorm? For example, I need to add a constraint to a column. I changed my model (simplified example below), but the AutoMigrate method, according to the docs, will not change column's constraints.

How do you achieve it then? I cannot find anything useful in the docs

Starting model:

type User struct {
    gorm.Model
    Name     string
}

I would like to update it like this:

type User struct {
    gorm.Model
    Name     string   `gorm:"not null"`
}

Answer 1

When adding a not null constraint, then a default value will also need to be added for when the existing records do not meet the new criteria. The definition could be something like:

type User struct {
    gorm.Model
    Name     string   `gorm:"not null;default:'fillertext'"`
}

As @putu said, ALTER TABLE will certainly work, but you would still need to add a default value initially to ensure the non-comforming rows meet the new requirements. Once this has been done you can remove the default value if you desire and the migration will work as intended from that point on.