gorm jsoninline

This is a struct tag in Golang that allows the fields of a struct to be flattened when serialized to JSON.

The inline keyword instructs the GORM library to flatten the fields of the struct into the parent struct when creating a table in the database. This can be useful when you want to combine multiple related structs into a single table.

For example, consider two structs Author and Book:

type Author struct {
    ID   uint   `gorm:"primaryKey"`
    Name string `gorm:"unique"`
}

type Book struct {
    ID        uint   `gorm:"primaryKey"`
    Title     string `gorm:"unique"`
    Author    Author `gorm:"foreignKey:AuthorID"`
    AuthorID  uint
    Published time.Time
}

When creating a table for the Book struct, GORM will create separate columns for Author.ID and Author.Name, even though they are related to the book's author.

To flatten the Author fields into the Book table, we can use the inline tag:

type Author struct {
    ID   uint   `gorm:"primaryKey"`
    Name string `gorm:"unique"`
}

type Book struct {
    ID        uint   `gorm:"primaryKey"`
    Title     string `gorm:"unique"`
    Author    Author `gorm:"foreignKey:AuthorID;constraint:OnUpdate:CASCADE,OnDelete:SET NULL" json:",inline"`
    AuthorID  uint
    Published time.Time
}

With json:",inline", the Author fields will be flattened into the Book struct when serialized to JSON.

For example, the JSON representation of a Book object would look like this:

{
    "ID": 1,
    "Title": "The Great Gatsby",
    "AuthorID": 2,
    "Name": "F. Scott Fitzgerald"
}