EncodableRecord

Encodes the record into database values.

Store in the container argument all values that should be stored in the columns of the database table (see databaseTableName()).

Primary key columns, if any, must be included.

struct Player: EncodableRecord {
    var id: Int64?
    var name: String?

    func encode(to container: inout PersistenceContainer) {
        container["id"] = id
        container["name"] = name
    }
}

It is undefined behavior to set different values for the same column. Column names are case insensitive, so defining both name and NAME is considered undefined behavior.

When the EncodableRecord type also adopts the standard Encodable protocol, you can use this dictionary to customize the encoding process into database rows.

For example:

// A key that holds a encoder's name
let encoderName = CodingUserInfoKey(rawValue: "encoderName")!

struct Player: PersistableRecord, Encodable {
    // Customize the encoder name when encoding a database row
    static let databaseEncodingUserInfo: [CodingUserInfoKey: Any] = [encoderName: "Database"]

    func encode(to encoder: Encoder) throws {
        // Print the encoder name
        print(encoder.userInfo[encoderName])
        ...
    }
}

let player = Player(...)

// prints "Database"
try player.insert(db)

// prints "JSON"
let encoder = JSONEncoder()
encoder.userInfo = [encoderName: "JSON"]
let data = try encoder.encode(player)

When the EncodableRecord type also adopts the standard Encodable protocol, this method controls the encoding process of nested properties into JSON database columns.

The default implementation returns a JSONEncoder with the following properties:

• dataEncodingStrategy: .base64
• dateEncodingStrategy: .millisecondsSince1970
• nonConformingFloatEncodingStrategy: .throw
• outputFormatting: .sortedKeys (iOS 11.0+, macOS 10.13+, tvOS 11.0+, watchOS 4.0+)

You can override those defaults:

struct Achievement: Encodable {
    var name: String
    var date: Date
}

struct Player: Encodable, PersistableRecord {
    // stored in a JSON column
    var achievements: [Achievement]

    static func databaseJSONEncoder(for column: String) -> JSONEncoder {
        let encoder = JSONEncoder()
        encoder.dateEncodingStrategy = .iso8601
        return encoder
    }
}

When the EncodableRecord type also adopts the standard Encodable protocol, this property controls the encoding of date properties.

Default value is .deferredToDate

For example:

struct Player: PersistableRecord, Encodable {
    static let databaseDateEncodingStrategy: DatabaseDateEncodingStrategy = .timeIntervalSince1970

    var name: String
    var registrationDate: Date // encoded as an epoch timestamp
}

When the EncodableRecord type also adopts the standard Encodable protocol, this property controls the encoding of UUID properties.

Default value is .deferredToUUID

For example:

struct Player: PersistableProtocol, Encodable {
    static let databaseUUIDEncodingStrategy: DatabaseUUIDEncodingStrategy = .string

    // encoded in a string like "E621E1F8-C36C-495A-93FC-0C247A3E6E5F"
    var uuid: UUID
}

A dictionary whose keys are the columns encoded in the encode(to:) method.

Returns a boolean indicating whether this record and the other record have the same database representation.

A dictionary of values changed from the other record.

Its keys are column names. Its values come from the other record.

Note that this method is not symmetrical, not only in terms of values, but also in terms of columns. When the two records don’t define the same set of columns in their encode(to:) method, only the columns defined by the receiver record are considered.