Fetching Data

A collection, or a query built from it with where, orderBy and limit, returns a list of models.

Read once

// Every document in the collection
final all = await odm.users.get();

// A query
final active = await odm.users
    .where(($) => $.isActive(isEqualTo: true))
    .orderBy(($) => ($.age(descending: true),))
    .get();

for (final user in active) {
  print('${user.name} is ${user.age}');
}

get accepts GetOptions to read from the cache or the server only:

final cached = await odm.users.get(const GetOptions(source: Source.cache));

Listen for changes

stream emits the full result list now and after every change to a matching document.

final subscription = odm.users
    .where(($) => $.isPremium(isEqualTo: true))
    .stream
    .listen((users) {
  print('Premium users: ${users.length}');
});

// Later
await subscription.cancel();

Each read of stream starts a new listener. In a Flutter widget, create the stream once (for example in initState) and pass it to a StreamBuilder.

Counting

To count documents without downloading them, use count(); see Aggregations.

final n = await odm.users.where(($) => $.isActive(isEqualTo: true)).count();

Using a query more than once

Queries are immutable values. Store one and call get, stream, or further builder methods on it as often as you like:

final adults = odm.users.where(($) => $.age(isGreaterThanOrEqualTo: 18));

final firstTen = await adults.limit(10).get();
final total = await adults.count();