Can you explain what the Embedded annotation means in the Room library?

The @Embedded annotation in the Room library is used to include the fields of one object into another database entity as part of its columns. This allows avoiding the creation of a separate table for the nested object and storing its fields directly in the parent entity's table.

For example, if you have a class Address with fields street and city, and you want to include it in the User entity, then using @Embedded, the street and city fields will be added as columns in the User table.

data class Address(
    val street: String,
    val city: String
)

@Entity
data class User(
    @PrimaryKey val id: Int,
    val name: String,
    @Embedded val address: Address
)

As a result, the User table will contain columns: id, name, street, city. This is convenient for data normalization and simplifying queries.