Records
A record is what you get back from .find() or .findOne(). Each record is a uniquely identifiable object that corresponds one-to-one with a physical database entry; e.g. a row in Oracle/MSSQL/PostgreSQL/MySQL, a document in MongoDB, or a hash in Redis.
var records = await Order.find();
console.log('Found %d records', records.length);
if (records.length > 0) {
console.log('Found at least one record, and its `id` is:',records[0].id);
}
JSON serialization
In Sails, records are just dictionaries (plain JavaScript objects), which means they can easily be represented as JSON. But you can also customize the way that records from a particular model are stringified using the customToJSON model setting.
Populated values
In addition to basic attribute data like email addresses, phone numbers, and birthdates, Waterline can dynamically store and retrieve linked sets of records using associations. When .populate() is called on a query, each of the resulting records will contain one or more populated values. Each one of those populated values is a snapshot of the record (or array of records) linked to that particular association at the time of the query.
The type of a populated value depends on what kind of association it is:
null, or a plain JavaScript object (if it corresponds to a "model" association)- an empty array, or an array of plain JavaScript objects (if it corresponds to a "collection" association)
For example, assuming we're dealing with orders of adorable wolf puppies:
var orders = await Order.find()
.populate('buyers') // a "collection" association
.populate('seller'); // a "model" association
// this array is a snapshot of the Customers who are associated with the first Order as "buyers"
console.log(orders[0].buyers);
// => [ {id: 1, name: 'Robb Stark'}, {id: 6, name: 'Arya Stark'} ]
// this object is a snapshot of the Company that is associated with the first Order as the "seller"
console.log(orders[0].seller);
// => { id: 42941, corporateName: 'WolvesRUs Inc.' }
// this array is empty because the second Order doesn't have any "buyers"
console.log(orders[1].buyers);
// => []
// this is `null` because there is no "seller" associated with the second Order
console.log(orders[1].seller);
// => null
Expected types / values for association attributes
The table below shows what values you can expect in records returned from a .find() or .findOne() call under different circumstances.
without a .populate() added for the association |
with .populate(), but no associated records found |
with .populate(), with associated records found |
|
|---|---|---|---|
Singular association (e.g. seller) |
Whatever is in the database record for this attribute (typically null or a foreign key value) |
null |
A POJO representing a child record |
Plural association (e.g. buyers) |
undefined (the key will not be present) |
[] (an empty array) |
An array of POJOs representing child records |
Modifying populated values
To modify the populated values of a particular record or set of records, call the .addToCollection(), .removeFromCollection(), or .replaceCollection() model methods.
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