import ballerina/io;

// `Person` type allows additional fields with `anydata` values.
type Person record {
    string name;
};

// `Employee` type allows additional fields with `anydata` values.
type Employee record {
    string name;
    int id;
};

// Adds an additional `id` field to `e`.
Employee e = {
    name: "James", id: 10
};

// You can assign an `Employee` type value to a `Person`.
Person p = e;

Person p2 = {
    name: "John", "country": "UK"
};

// You can assign a `Person` type value to a `map`.
map<anydata> m = p2;

public function main() {
    io:println(p);
    io:println(m);
}

Open records

Record types are open by default. They allow fields other than those specified. The type of unspecified fields is anydata. Records are maps. Open records belong to map<anydata>. Use quoted keys for fields not mentioned in the record type.

 
import ballerina/io;

type Person record {
    string name;
};

Person type allows additional fields with anydata values.

type Employee record {
    string name;
    int id;
};

Employee type allows additional fields with anydata values.

Employee e = {
    name: "James", id: 10
};

Adds an additional id field to e.

Person p = e;

You can assign an Employee type value to a Person.

Person p2 = {
    name: "John", "country": "UK"
};

map<anydata> m = p2;

You can assign a Person type value to a map.

public function main() {
    io:println(p);
    io:println(m);
}

bal run open_records.bal
{"name":"James","id":10}
{"name":"John","country":"UK"}