Dev Notes

Updating database field to NULL in GORM using struct

Muhammad Redho Ayassa's photo
Muhammad Redho Ayassa
·

1 min read

Background

When I was using GORM as the ORM in Go, I discovered that we cannot update a field into NULL with struct, even though we use a pointer as the type.

For example, if we set nil to the Name and execute the Updates method in GORM, the name field won't be updated into NULL .

type User struct {
    Id   int64
    Name *string
    Age  *int32
}

Solution

We can use sql.Null* type for the field.

For instance, we can use sql.NullString for supporting NULL value for the string data type. We can use sql.NullBool for boolean.

See the complete list in this package.

Example

Suppose we want to set the name field into NULL. We can create the struct as follows:

type User struct {
    Id   int64
    Name sql.NullString
    Age  *int32
}

And then set the Name with:

user := User{}
// setting Valid = false for updating the value into NULL
u.Name = sql.NullString{String: "", Valid: false}
db.Update(&user)

Trade-off

We need to map the field into sql.NullString or other nullable types before updating data to the database.

Go LanguagePostgreSQL